CBSE Class 10

NCERT Solutions for Class 10 English Main Course Book Unit 1 Chapter 1 Do Indians Get Enough Sleep ? are part of NCERT Solutions for Class 10 English. Here we have given NCERT Solutions for Class 10 English Main Course Book Unit 1 Chapter 1 Do Indians Get Enough Sleep ?.

CBSE Class 10 English Main Course Book Unit 1 Health and Medicine Chapter 1 Do Indians Get Enough Sleep ?

TEXTUAL EXERCISES

Question 1.
Now that you have read a substantial part of the feature article, work with your partner and jot down at least five reasons that, according to you, are mainly responsible for Indians today not getting the desired quota of sleep each night. Share your views with other pairs of students in your class.
Answer:
Five reasons responsible for Indians today not getting the desired quota of sleep each night are :

1. worries due to fast pace of life
2. relating to living problems
3. to and fro travel from home and office
4. trying to catch up with time
5. worries about studies, career, peer competition
6. absence of proper and balanced food
7. gap between what mind thinks and what actually is available
8. ambitions without proper props
9. parents discrimination

Note : Students to add a few more from their side and share their views with the other pairs of students.

Question 2.
On the basis of your reading of the article, answer the following questions :

(a) The direct result of lack of sleep is _____.
(b) Why is it important for physicians to ‘wake up’ to sleep disorders ? How will it help ?
(c) What do you understand by sleep deficit ? Why does the amount of sleep required to rejuvenate people vary from one person to another ?
(d) Why does the writer refer to the ‘early to bed …’principle ?

Answer:

(a) sleep disorders/many ailments.

(b) It is important for physicians to ‘wake up’ to sleep disorders because sleep disorders are behind many ailments. If sleep history is considered in evaluating a patient, it will help greatly in diagnosing the ailments.

(c) By ‘sleep deficit’ I mean the sleep that should have been there but was not had due to various reasons. The amount of sleep required to rejuvenate people varies from person to person. It is so because the physiological aspects and living conditions are different from one to another.

(d) The writer refers to the ‘early to bed …’ principle because it is just the best for a healthy person. However, it may not be possible today.

Question 3.
Now, write a letter to your school going younger brother or sister who is sleep deprived. Advise him or her to make life style changes to his/her daily schedule in order to get the desired hours of sleep daily.
Work in pairs and follow the CODER (Collect, Organize, Draft, Edit, Review) steps recommended for writing.

Language Tips :
(a) Remember to use the imperative form of sentences mostly.
E.g. “Drink a lot of water and take at least a fifteen minute stroll after dinner on a regular basis.”

(b) For the sake of introducing variety into your writing, use other forms of sentences making statements or asking questions, but consider the possibility of using modals like “should”, “must”, “may”, “might”, etc or using words or expressions that we usually employ when we advise others.
E.g. “You are recommended / advised to ……………… ”
“You ought to…”
“You must not forget to…”
“It is important to…”

Answer:

98-Sector 14A
Rohini, New Delhi
15 September, 20 – –

My dear Anil

I hope everything at your end is fine. I have learnt that you have started being sleep deprived due to various reasons. It is really very sad to know. There may be some valid reasons. However, I am sure if you change your life style, you can remain healthy.

First of all, I would say that sleep deprivation may be called the mother of all diseases. Leaving the reasons behind it aside you must think more of changing your daily routine. For instance, you must go to bed and rise at fixed times. Eat a balanced diet. Avoid junk food, avoid eating street food. Take plenty of water. Dwell more on eating your homemade food. Play for some time in between doing your homework. Don’t view television for I longer hours. Avoid sitting before the computer for hours together and in one posture. Snatch a few minutes in between, if you have to use it, and stretch your body. Avoid the effect of any peer competition. Stop giving a long rope to unrealistic goals.

I am sure if you pursue your goal with a strict regularity you’ll enjoy a sound sleep. You’ll also succeed in your goals.

Yours sincerely
_________________

Question 4.
(a) Phrasal verbs are “multi-word verbs”. These verbs consist of a basic verb + another word or words. The other word (s) can be prepositions and/or adverbs that modify or change their meaning. For example ‘give up’ is a phrasal verb that means ‘stop doing’ something, which is very different from ‘give’. In the article that you have just read there are a few phrasal verbs like :

• pull off : Manage to do something difficult or tricky/to steer or turn a vehicle off the road
• roll down : roll down (something) or roll (something) down : to move (something) down especially by turning handle
• head for : to go or cause to go (towards)
• woke up : arose from sleep/realized

Now look through the unit of Health and Medicine, figure out the phrasal verbs that you come across and list them.

Answer:

Some more phrasal verbs from the Unit are given below :

(b) Find words from the article which mean the saine as the following :

Answer:

Question 5.
Read the concluding part of the article on whether we get enough sleep these days.

Concluding Part of the Article

SUMMARY

Sleep is very important for one’s health. Without it we can invite health problems, like heart disease, diabetes, obesity and depression.

Stanley Coren, noted professor of psychology and author of‘Sleep Thieves’, says that not sleeping enough can affect one’s immune system. He says that the immune system works best when one is sleeping. Then natural killer cells are generated. These are produced in the bone marrow and found in the blood and lymph fluid. They are the part of the body’s defence mechanism against viruses etc, even cancer.

In a study conducted in Turkey it was found that after 24 hours of sleep deprivation these natural killer cells declined by 37%. In another study in the U.S.A. this percentage was 72%. This activity returns to normal when we begin to get proper sleep. But sleep deprivation does more damage to our immune system.

Dr. Michael Sole, a Canadian cardiologist, says that there is a higher rate of heart failure among people with sleep disorders and sleep disturbances. He emphasises that C-reactive protein is tjie evidence that indicates the heart disease risk.

Researches in various universities all over the world have discovered that sleep loss can reduce the body’s ability to regulate hormones etc. In a study at the University of Chicago sleep from eight hours a night was reduced to four hours. They noted changes in bodies. Sleep disturbances disturbed glucose in tolerance and insulin resistance causing heart diseases. Dietician Ramona Josephson notes that insufficient sleep may effect three hormones contributing to obesity. Increased hormones resulting from sleep loss make us eat more.

Sleep is important in keeping waistline trim. It also ensures a balanced brain activity. During sleep brain neurotransmitters get replenished. In the absence of sleep these brain chemicals become depleted. This leads to emotional disturbances like depression, anxiety, sadness, anger and irritation.

Question 6.
Find the words from the final part of the above article that you have just finished reading which mean the same as the words or group of words given below.

(a) Vital, very important (para 1): (i) _________

(b) the quality of being prone to or open (ii) _________
to dangers, like a disease or infection or a weakness (para 1):

(c) a wide range (para 1) : (iii) _________

(d) very badly in a damaging way (iv) _________
(para 4):

(e) a problem that has persisted for (v) _________
quite some time (para 5):

Answer:

(i) crucial
(ii) susceptibility
(iii) array
(iv) adversely
(v) chronic

Question 7.
Choose the appropriate options to complete the sentences below.

1. Lack of sleep

(a) decreases laziness.
(b) weakens the body’s capacity to combat diseases.
(c) helps youngsters do well in their examinations.
(d) prevents a person from gaining weight.

2. Natural killer cells

(a) make a person look old pretty quickly.
(b) are produced in large numbers when we stay awake.
(c) help us fight viruses and bacteria.
(d) work well even for sleep-deprived people.

3. C-reactive protein

(a) when produced more in the body causes heart failure.
(b) prevents us from having a good night’s sleep.
(c) helps us to sleep peacefully.
(d) assists in destroying natural killer cells.

4. If we don’t sleep well,

(a) we may lose our appetite.
(b) we may become very thin.
(c) our brain may stop functioning in a balanced manner.
(d) production of brain chemicals increases.

Answer:

1. (b) weakens the body’s capacity to combat diseases.
2. (c) help us fight viruses and bacteria.
3. (a) when produced more in the body causes heart failure.
4. (c) our brain may stop functioning in a balanced manner.

Question 8.
Lack of sleep has a direct effect on the production of three hormones and brain neurotransmitters, which in turn has a bearing on our health. Complete the table below to show the above.

Answer:

(i) appetite-suppressing (hormone) (weakness)
(ii) in obesity/suppressing appetite
(iii) hunger pangs
(iv) increase in hunger pangs
(v) stress (hormone)
(vi) increase in fat storage
(vii) get depleted,
(viii) sadness, anger and irritation, depression etc

Question 9.
You have read about sleep deprivation and the ill effects it has on human beings. There are other work areas where youngsters remain sleep deprived and fall a pray to ill health. Listen carefully to some of the comments made about the business process outsourcing (BPO) sector which is part of the IT-enabled industry and do the activity. [Page 239 and 240 of Main Course Book]


WORD-NOTES

While you listen, complete the following statements by choosing the right option :

1. According to the speaker, call centre work is insensitive because :

(i) the people cannot go to the toilets and need to concentrate very hard
(ii) the people are expected to attend to all the calls that come through to them
(iii) it requires unflagging concentration throughout the day with minimum breaks for meals or visits to the toilet
(iv) the people are expected to work on the computer all day long

2. People working at call centres are not allowed to leave their desks because :

(i) the managers do not want them to waste time smoking
(ii) they have to attend the calls which come in one after the other
(iii) they have to work at their computers all day long
(iv) they are paid very well

3. The targets that have to be met by the call centre employees have been called unrealistic because :

(i) they have to attend to too many calls in one day
(ii) they have to attend to double the calls than call centre workers in other countries
(iii) it is not humanly possible to attend all the calls that come through to them
(iv) the employees fall sick after working at these places

4. Closed circuit cameras have been installed in these offices to monitor

(i) whether the workers are smoking
(ii) whether the workers are resting at their desks
(iii) whether the workers are attending their calls without wasting a minute
(iv) whether the workers are visiting the toilets too often

5. The statistics about the health problems suffered by these people are

(i) 13%-headaches, 3%-eye fatigue, 23% indigestion and constipation
(ii) 3%-headaches, 13%-eye fatigue, 23% indigestion and constipation
(iii) 23%-headaches, 3%-eye fatigue, 13% indigestion and constipation
(iv) 13%-headaches, 13%-eye fatigue, 23% indigestion and constipation

6. That most people are not happy with their jobs in a call centre can be inferred from the fact that:

(i) they are under constant surveillance
(ii) they have to speak incessantly on the telephone
(iii) they have to stare at the computer screen all day long
(iv) they do not stay in the job for more than three years

Answers:

1. (iii) it requires unflagging concentration throughout the day with minimum breaks for meals or visits to the toilet
2. (ii) they have to attend the calls which come in ‘one after the other
3. (ii) they have to attend to double the calls than call centre workers in other countries
4. (iii) whether the workers are attending their calls without wasting a minute
5. (ii) 3%-headaches, 13%-eye fatigue, 23% indigestion and constipation
6. (iv) they do not stay in the job for more than three years

Question 10.
You have listened to the woes of working in a call centre. There are a number of other jobs which involve health hazards. However, modern advancements and developments in various therapies have improved our living conditions. Given below are different view points. In groups of four, discuss and add to these views :

Answer:

Meant for classroom activity. A sample of discussion is given below :

A : I personally feel that today the pace of life has become very fast. There is a lot of stress and pressure in everybody’s life …………

B : I agree with A. I see that a student has to cope up with lot of homework, peer competition, meeting parents’ ambitions etc. Don’t you see how students spend a day ? They have become the beasts of burden due to the stress of studies.

A : Then see the adults ! Do you see cheerfulness and joy on their faces ? Never ! They are always under stress and tension. This takes even small moments of joy from their lives. Worries of life have simply made them mad ………..

C : I am sorry, I don’t agree with you. They may be stressed but it is their own doing. I think that today men are more comfortable than their ancestors. See the advancement in every field of human activity. However, means of travel, medical facilities, health awareness, availability of medicines, new therapies etc, have increased life expectancy.

D : I agree with C. People today are more aware about their health. In the past we didn’t have yoga classes in parks etc. Now people are health conscious and do yoga and other physical exercises and eat a balanced diet.

E : Besides this, laughter therapies are there. We see adults laughing and clapping. These therapies have been found really beneficial for today’s stress and tension. Even absence of stress, you know, helps in keeping good health.

C : I feel that today human beings are comfortably placed in life than their ancestors. This all is because of scientific and technological advancement in almost every branch of life. Then education has brought a kind of revolution. Old treatises of medicines have been translated. Ayurvedic, Homeopathic and Unani medicines have rendered a great service to human health.

D : I see that there is no point in being pessimistic. We must live life full and with a positive outlook. We must sleep well, eat well and laugh and laugh. Of course, we mustn’t shun our work as work is worship…

We hope the NCERT Solutions for Class 10 English Main Course Book Unit 1 Chapter 1 Do Indians Get Enough Sleep ? help you. If you have any query regarding NCERT Solutions for Class 10 English Main Course Book Unit 1 Chapter 1 Do Indians Get Enough Sleep ?, drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 10 English Literature Chapter 1 Two Gentlemen of Verona are part of NCERT Solutions for Class 10 English. Here we have given NCERT Solutions for Class 10 English Literature Chapter 1 Two Gentlemen of Verona.

NCERT Solutions for Class 10 English Literature Chapter 1 Two Gentlemen of Verona

TEXTUAL EXERCISES
(Page 3,8)

Question 1.
What are the qualities of a “gentleman” ? Work with your partner and complete the following web-chart by listing the qualities of a gentleman.

Answer:

A gentleman does have not only consideration for others but willingness to keep them. For a real gentleman, consideration for others is more important than his own interest.

Question 2.
Based on your discussion above, what do you think the story is about ?

• …………………………………………………………
• …………………………………………………………

Answer:

• I think the story is about two gentlemen of Verona who may do good things to and for others than their own.
• Besides this, the story may be about them in displaying gentlemanly qualities in their deeds. These may have been done by them for others.

Question 3.
Now read the story given below. Your teacher will use a variety of techniques for different parts of the story e.g.

• Silent reading
• One student reading aloud to the whole class
• Students reading in small groups
• Dramatised reading in small groups

Answer:

• Activity meant for class level.
• No questions are asked here.

Question 4.
Based on your reading of the story answer the following questions by ticking the correct options.

1. The driver did not approve of the narrator buying fruit from the two boys because

(a) the boys were untidy and poorly dressed
(b) the strawberries were not fresh
(c) they were asking for a heavy price
(d) the driver did not approve of small boys who worked

2. The narrator was most impressed by the boys’

(a) desire to earn money
(b) willingness to work
(c) ability to perform many tasks
(d) sense of fun

3. Nicola was not pleased when Jacopo asked the narrator to drive them to Poleta as he

(a) did not want a stranger to become involved with their plans
(b) preferred going to Poleta by train so that he could enjoy the scenery
(c) did not want to ask anyone for favours
(d) did not want to take help from someone he did not know well

4. The narrator did not go inside Lucia’s room as

(a) he did not want to intrude into their privacy
(b) he thought that the boys would object
(c) Lucia would not welcome a stranger
(d) the boys would feel he was spying on them

5. The boys were the first to join the resistance movement against the Germans because

(a) the Germans had hurt their sister
(b) the Germans ruled the city
(c) the Germans had ruined their family
(d) the Germans had destroyed their home

6. The author did not speak to the boys on their return journey because

(a) he thought the boys would prefer to keep their secret
(b) he thought the boys were ashamed of their sister’s condition
(c) he thought they wouldn’t tell him the truth
(d) he thought the boys might ask him for money for their sister

Answer:

1. → (a) the boys were untidy and poorly dressed
2. → (c) ability to perform many tasks
3. → (a) did not want a stranger to become involved with their plans
4. → (a) he did not want to intrude into their privacy
5. → (c) the Germans had ruined their family
6. → (a) he thought the boys would prefer to keep their secret.

Question 5.
What do you understand by the following statements ?
(a) “We do many things, sir,” Nicola answered seriously. He glanced at us hopefully.
(b) He coloured deeply under his sunburn, then grew pale.
(c) He smiled uncomfortably. “Just plans, sir,” he answered in a low voice.
(d) Yet in both these boyish faces there was a seriousness which was far beyond their years.

Answer:

(a) By this statement I understand that Nicola doesn’t have any hesitation in doing anything which may serve his own purpose. Besides this, he means that he is ready to do as many things as are humanly possible.

(b) When the narrator asked Nicola what he did with his money, he didn’t find an instant answer. It was perhaps that he couldn’t gather enough courage to tell the truth. Or he might have wanted not to tell anything about his family secrets to a stranger.

(c) From this statement it is clear that Nicola acts really like a mature person. He doesn’t want that strangers should know their secret plans of life.

(d) This statement clearly reveals that both Nicola and Jacopo had grown very mature and considerate in earning money. It was for getting their sister cured of her disease. Doing things for others at the cost of self makes one considerate and mature. Both Nicola and Jacopo had had this effect in what they did for their sister.

Question 6.
Answer the following questions briefly.
(а) Why didn’t Luigi, the driver, approve of the two boys ?
(b) Why were the narrator and his companion impressed by the two boys ? (V. Imp.)
(c) Why was the author surprised to see Nicola and Jacopo working as shoeshine boys ?
(d) How were the boys useful to the author ? (CBSE 2015)
(e) Why were the boys in the deserted square at night ? What character traits do they exhibit ?
(f) The narrator asks the boys, “Must you work so hard? You both look rather tired.” The boys reply, “We are not complaining, sir. ” What do you learn about the boys from their reply ? (V. Imp.)
(g) When the narrator asks the boys about their plans, they are evasive. Why don’t they disclose their problems ? (V. Imp.)

Answer:

(a) Luigi didn’t approve of the two boys for two reasons. First, they were selling wild strawberries. Second, they looked very dirty and shabby. From their appearance they looked like cheats, thieves and what not.

(b) The narrator and his companion were impressed by the two boys because of their mutual love and capacity to work hard. They cared much more for their sister than their own selves. Such human beings are rare.

(c) The author was surprised to see Nicola and Jacopo working as shoeshine boys. It was because the previous day he had seen them selling wild strawberries. This change naturally created a doubt about them in the author’s mind.

(d) The boys were useful to the author because they brought the things that he wanted. They helped him in getting American cigarettes, seats for the opera or knowing the name of a good restaurant. They could be depended upon.

(e) The boys were in the deserted square at night waiting for the bus to sell newspapers. They exhibit their readiness for hard work, determination and devotion as character traits.

(f) I learn about the boys from their reply that both of them have seen much harder days. So they aren’t afraid of anything, even the worst. Secondly, they understand it well that hard work shall end their miseries.

(g) Both the boys are evasive and don’t disclose their plans because they find the author as a stranger. Since they have seen much dark days in their lives, they have lost faith in the people. That’s why, they don’t want to create more troubles in sharing their personal matters with outsiders. They may also think that there may be a lion in a sheep’s clothing.

Question 7.
Discuss the following questions and write the answers in your notebook.
(a) Appearances are deceptive. Discuss with reference to the two boys. (V. Imp.)
(b) Do you think the boys looked after Lucia willingly ? Give reasons for your answer.
(c) How does the story ‘Two Gentlemen of Verona’promise hope for society ? (V. Imp.)

Answer:

(a) It is a fact that appearances are deceptive and all that glitters is not gold. Nicola and Jacopo look street urchins, thieves and what not. No one can guess from their appearances that they could have great qualities of gentlemanliness and humanism. In that they had to forget their own interests. What they do for their sister is just superb and unparalleled.

(b) Yes, I think both Nicola and Jacopo looked after Lucia willingly due to their upbringing. Their family had once been comfortable and cultured. Their father was a well-known singer and they led a good life. In such an atmosphere the children couldn’t think of negative values like selfishness and ingratitude. So due to inborn qualities of familial relationships, both the boys looked after Lucia willingly and selflessly. Secondly, she was their only sister and a member of their family.

(c) The ‘Two Gentlemen of Verona’ promises hope for the society especially in the modern times of broken family relationships. Today, brothers are fighting with brothers ; sons are beating their parents. Old parents are being shunted out by their children. To lead life in such a hell it is desirable that children like Nicola and Jacopo should be born. Such boys can repair the breaking relationships due to selfishness, materialism and greed.

Question 8.
Look at the italic words in the following examples.

(a) We bought their biggest basket, then set off toward town.
(b) One night we came upon them in the windy and deserted square.
(c) He bit his lip, then in a rather put out tone he said, ‘Very well.’
(d) I shook my head and turned away.

Here are a few more. Match the phrases to their meanings.

Answer:

Now use the phrases given above to complete the following sentences.

1. The landlord was suspicious of the two men staying in his flat so he called the police and …………. them ………….
2. Early in the morning we packed our bags and …………. for a hike over the mountain.
3. Janvi …………. some photographs of her grandfather in the old trunk.
4. My father …………. his own business 10 years ago.
5. The Bank …………. Paul’s request for a loan.
6. The Corporation’s decision to reduce the leave of the employees …………. a lot of opposition.

Answer:

1. turned …………. to
2. set off
3. came across
4. set up
5. turned down
6. set off

Question 9.
Two Gentlemen of Verona is written in the first person. ……………………
Rewrite any part of the story you like in the third person.
Answer:

• Students can pick out any part of the story and rewrite the same in the third person (that is, indirect speech.)
• Here below is given one such example:
• The narrator suggested to Nicola that he must be saving up to emigrate to America. At this Nicola looked at him sideways and spoke with an effort. He replied that they would greatly like to go to the States. But at present, they had other plans.
• At this the narrator asked what plans they had.
• Nicola smiled uncomfortably and politely told him in a low voice that they had just plans.

Question 10.
The narrator realises why Nicola and Jacopo work so hard. Yet he does not go r in to meet their sister nor does he speak to them about what he learns from the nurse. Working in groups, discuss the following aspects of the story and share your views with the class.
(a) The love and devotion, and the family values Nicola and Jacopo display. (Imp)
(b) Their pride in themselves and their family. (Imp)
(c) The trust they place in the narrator.
(d) The reason the narrator does not disclose to them that he knows their secret.

Answer:

(a) The love, devotion and the family values that Nicola and Jacopo display are just unique and rare. These two children should have been in schools studying. But see their childhood ! They are spending it not enjoying anything but for their sister Lucia. Their sole aim is to see their ailing sister stand on her own legs. For that they are doing even the worst job. Secondly, they don’t care for anything, sleep, food, clothes, shelter, etc. But they care for what is good and abiding. For them their family values, love for sister and devotion are more important than anything. And they put these into practicality even if they have to lose their childhood. Due to this the narrator calls them ‘Two Gentlemen of Verona’.

(b) Both Nicola and Jacopo have self-pride and self-respect to the maximum. They are precocious. They have learnt many things in a little period of their life. The narrator wants to help them but they refuse excepting going in his car to Poleta. The narrator wants to know about their plans behind earning money. But they tell nothing to him. It may be because they trust no one. Or it may be due to pride and their family values.

(c) But both Nicola and Jacopo start putting some faith in the narrator as they get ready to go to Poleta in his car. But to some extent, leaving this aside, they keep themselves reserved. However, they answer to the narrator’s questions honestly and truthfully. Due to reposing their faith in him they open out to him. They then tell many things relating to their lives.

(d) The reason for this is that he doesn’t want to hurt their self-respect. If he tells them they may feel hurt because they have in their blood things of good family and a respectable life. It is a fact that such persons like Nicola and Jacopo have much sense of self-pride and self-respect.

Question 11.
As the narrator, write an article on the lesson of love, faith and trust that you have learnt from the two young boys of Verona. (V. Imp.)
Answer:
Two little boys’ love, faith and trust
Truly love, affection, faith and trust are invaluable values of human life. One can say that these can be inborn and may be acquired. But it would be convincing that these values are more inborn than acquired. God has, perhaps, bestowed certain people with these traits like Mother Teresa and Florence Nightingale. They sacrificed their selves for the sufferers. They nursed them with these invaluable assets. This fact is also applicable to two boys of Verona.

Nicola, the elder was 13 and Jacopo, his brother was 12. Both the brothers had had a cultured and comfortable life before the war. The war killed their father and just ruined their family. A bomb explosion brought them and their sister Lucia in the streets. But the courage and survival instinct of the boys couldn’t be killed. Lucia contracted TB and this broke the spirit of the boys but not for long. They did various odd jobs. These were selling wild strawberries, hawking newspapers, selling fruits and running errands. They slept on roadsides. They wore dirty clothes and never cared for themselves. They earned money honestly to pay for Lucia’s medical expenses.

It was the power of sheer love, faith and trust that they showed in whatever they did and were successful. Truly, both the brothers were the finest examples of these values.

Question 12.
After her brothers’ visit, Lucia writes a page in her diary about her past life and her present situation. As Lucia write the diary entry in about 150 words.
Answer:
Sunday, 15th September, 20 – 9:30 pm

How glad I was to see my loving brothers Nicola and Jacopo! This time they came with a stranger who brought them in his car. I can’t repay my brothers’ doing things for me. In fact, they have sacrificed their childhood for me. How they spend their time, going hungry and without sleep just for me shakes me much! But I hope such a time shall vanish soon. I have been progressing well due to their care and hope to start dancing for a career. Then we shall live together and earn a lot.

I have not forgotten our comfortable and cultured life. Our father was a well-known singer and we had been leading a pretty comfortable life. I had been training as a singer. But due to war and a bomb explosion everything finished. But all this didn’t discourage my brothers. I don’t know what and how they earn for meeting my expenses. But one thing is there. They won’t do any dubious kind of activity to earn money. We all have had good and virtuous traits of our character. We may suffer much but we won’t compromise with our family values. Nor will Nicola and Jacopo. Our bad days shall soon be over. I pray to God to make me disease-free soon so that I may take a good care of my responsibilities towards my angelic brothers.
Lucia

Question 13.
Listen to an excerpt from the diary of a 13 year old girl Zlata Fillipovic who writes of the horrors of war in Sarajevo in her book Zlata’s Diary.
Based on your listening of the passage, complete the following statements.

1. The first sign of approaching war was ………….
2. The family went into the cellar when ………….
3. The ‘awful cellar’ was the only place that could save their lives because ………….
4. Zlata’s friend, Nina died when ………….
5. Zlata and her father were worried about her mother’s safety because ………….

Answer:

1. on 14 April
2. the shooting started around noon on 2 May.
3. it was underground and pounding shells of guns etc, couldn’t reach it.
4. a shrapnel got lodged in her brain.
5. one shell exploded in the market when she was nearby it and she hadn’t come home.

We hope the NCERT Solutions for Class 10 English Literature Chapter 1 Two Gentlemen of Verona help you. If you have any query regarding NCERT Solutions for Class 10 English Literature Chapter 1 Two Gentlemen of Verona, drop a comment below and we will get back to you at the earliest.

NCERT Exemplar Solutions for Class 12 Biology chapter 5 Principles of Inheritance and Variation

These Solutions are part of NCERT Exemplar Solutions for Class 12 Biology. Here we have given NCERT Exemplar Solutions for Class 12 Biology chapter 5 Principles of Inheritance and Variation

Multiple Choice Questions

Question 1.
All genes located on the same chromosome
(a) form different groups depending upon their relative distance
(b) form one linkage group
(c) will not from any linkage groups
(d) form interactive groups that affect the phenotype.
Answer:
(b) : Linked genes are the genes which occur on the same chromosome. ,A linkage group is a physical association of linked genes which are normally inherited together except for crossing over.

Question 2.
Conditions of a karyotype 2n ± 1 and 2n ± 2 are called
(a) aneuploidy
(b) polyploidy
(c) allopolyploidy
(d) monosomy.
Answer:
(a) : The chromosomal disorders are caused due to absence or excess or abnormal arrangement of one or more chromosomes. Failure of segregation of chromatids during cell division cycle results in the gain or loss of chromosome(s), is called aneuploidy. For example, Down’s syndrome results due to gain of extra copy of chromosome 21. Similarly, Turner’s syndrome results due to loss of an X chromosome in human females.

Question 3.
Distance between the genes and percentage of recombination shows
(a) a direct relationship
(b) an inverse relationship
(c) a parallel relationship
(d) no relationship.
Answer:
(a) : Linkage is the phenomenon of physical association of genes on a chromosome and recombination is the generation of non- parental gene combinations. Strength of the linkage between two genes is inversely proportional to the distance between the two, i.e., two linked genes show higher frequency of crossing over (recombination) if the distance between them is higher and lower frequency if the distance is small. But distance between gene has a direct relationship with percentage of recombination because with increase in distance between genes, percentage of recombination increases.

Question 4.
If a genetic disease is transferred from a phenotypically normal but carrier female to only some of the male progeny, the disease is
(a) autosomal dominant
(b) autosomal recessive
(c) sex-linked dominant
(d) sex-linked recessive.
Answer:
(d) : The sex linked recessive disease shows its transmission from unaffected carrier female to some of the male progeny e.g., haemophilia. The heterozyous female (carrier) of haemophilia may transmit the disease to sons. The possibility of a female becoming a haemophilic is extremely rare because mother of such a female has to be at least carrier and the father should be haemophilic.

Question 5.
In sickle cell anaemia glutamic acid is replaced by valine. Which one of the following triplets codes for valine?
(a) GGG
(b) A AG
(c) GAA
(d) GUG
Answer:
(d) :The sickle-cell anaemia is caused by the substitution of glutamic acid (Glu) by valine (Val) at the sixth position of the beta globin chain of the haemoglobin molecule. The substitution of amino acid in the globin protein results due to the single base substitution at the sixth codon of the beta globin gene from GAG to GUG. The mutant haemoglobin molecule undergoes polymerisation under low oxygen tension causing the change in the shape of the RBC from biconcave disc to elongated sickle like structure.

Question 6.
Person having genotype /^A /^B would show the blood group as AB.This is because of
(a) pleiotropy
(b) codominance
(c) segregation
(d) incomplete dominance.
Answer:
(b) : ABO blood groups are controlled by the gene I. The plasma membrane of the red blood cells has sugar polymers that protrude from its surface and the kind of sugar is controlled by the gene. The gene (I) has three alleles I^A, I^B and i. The alleles I^A and /^B produce a slightly different form of the sugar while allele i does not produce any sugar. Because humans are diploid organisms, each person possesses any
two of the three I gene alleles. I^A and /^B are completely dominant over /, in other words when I^A and i are present then only I^A expresses (because i does not produce any sugar), and when /^B and i are present I^B expresses. But when I^A and /^B are present together they both express their own types of sugars, this is because of codominance. Hence, in this case red blood cells have both A and B types of sugars.

Question 7.
ZZ/ZW type of sex determination is seen in
(a) platypus
(b) snails
(c) cockroach
(d) peacock.
Answer:
(d) : In birds and some reptiles both the sexes possess two sex chromosomes but unlike human beings the females contain heteromorphic sex chromosomes (AA + ZW) while the males have homomorphic sex chromosomes (AA + ZZ). Because of having heteromorphic sex chromosomes, the females are heterogametic (female heterogamety) and produce two types of eggs, (A + Z) and (A + W). The male gametes or sperms are of the one type (A + Z). 1:1 sex ratio is produced in the offspring.\

Question 8.
A cross between two tall plants resulted in offspring having few dwarf plants. What would be the genotypes of both the parents?
(a) TTandTt
(b) TtandTt
(c) TT andTT
(d) Tt and tt
Answer:
(b) : The genotypes of both the parents are :

Question 9.
In a dihybrid cross, if you get 9:3 :3 :1 ratio it denotes that
(a) the alleles of two genes are interacting with each other
(b) it is a multigenic inheritance
(c) it is a case of multiple allelism
(d) the alleles of two genes are segregating independently.
Answer:
(d) : Cross involving two contrasting characters is called dihybrid cross or a two factor cross. The two factors of each trait assort at random and independent of the factors of other traits at the time of meiosis (gametogenesis) and get randomly as well as independently rearranged in the offspring producing both parental and new combinations of traits. This explained the law of independent assortment given by Mendel.

Question 10.
Which of the following will not result in variations among siblings?
(a) Independent assortment of genes
(b) Crossing over
(c) Linkage
(d) Mutation
Answer:
(c) : Linkage will not result in variations among siblings because linked genes occur on the same chromosome and are transmitted together. In linkage there is a tendency to maintain the parental gene combinations except for occasional crossovers.

Question 11.
Mendel’s law of independent assortment holds good for genes situated on the
(a) non-homologous chromosomes
(b) homologous chromosomes
(c) extra nuclear genetic element
(d) same chromosome.
Answer:
(b) : According to the Mendel’s law of independent assortment, the pairs of “factors” segregate independently of each other when germ cells are formed. Homologous chromosomes synapse during meiosis and then separate to segregate independently into different cells which establishes the quantitative basis for segregation and independent assortment of hereditary factors.

Question 12.
Occasionally, a single gene may express more than one effect. The phenomenon is called
(a) multiple allelism
(b) mosaicism
(c) pleiotropy
(d) polygeny
Answer:
(c) : Pleiotropic allele has more than one effect in an organism. For example, the allele that causes the erythrocytes to have a distorted form in sickle-cell anemia also causes these blood cell to rupture easily.

Question 13.
In a certain taxon of insects some have 17 chromosomes and the others have 18 chromosomes. The 17 and 18 chromosome­bearing organisms are
(a) males and females, respectively
(b) females and males, respectively
(c) all males
(d) all females.
Answer:
(a) : In certain insects XX – XO type of sex determination is observed where females have autosomes + i pair of sex chromosomes while males have autosomes + 1 sex chromosome.

Question 14.
The inheritance pattern of a gene over generations among humans is studied by the pedigree analysis. Character studied in the pedigree analysis is equivalent to
(a) quantitative trait
(b) Mendelian trait
(c) polygenic trait
(d) maternal trait
Answer:
(b) : Pedigree analysis is study of pedigree for the transmission of particular trait and finding the possibility of absence or presence of that trait in homozygous or heterozygous state in a particular individual.  It indicates that Mendel’s principles are also applicable to human genetics with some modifications like quantitative inheritance, sex linked characters and other linkages.

Question 15.
It is said that Mendel proposed that the factor controlling any character is discrete and independent. His proposition was based on the
(a) results of F₃ generation of a cross
(b) observations that the offspring of a cross made between the plants having two contrasting characters shows only one character without any blending
(c) self pollination of F₁ offsprings
(d) cross pollination of F! generation with recessive parent.
Answer:
(b) : When plants having two contrasting characters are crossed, F, generation shows dominant phenotype and the recessive phenotype is not lost but appears in F₂ generation. This suggested that there is no blending of Mendelian factors in Fj generation but they stay together and only one of them is expressed. At the time of formation of gametes, these two factors obviously separate or segregate, otherwise recessive type will not appear in F₂ generation. The gametes which are formed are always pure for a particular character. That is why it is called as ‘principle of segregation’ or Taw of purity of gametes’.

Question 16.
In the F₂ generation of a Mendelian dihybrid cross the number of phenotypes and genotypes are
(a) phenotypes-4;genotypes-16
(b) phenotypes-9; genotypes-4
(c) phenotypes-4; genotypes-8
(d) phenotypes-4; genotypes-9.
Answer:
(d) : Mendel performed crosses involving two characters called as dihybrid cross. Results of the dihybrid cross where the two parents different in two pairs of contrasting traits i.e. seed colour and seed

Question 17.
Mother and father of a person with ‘O’ blood group have’A’and’B’blood group respectively. What would be the genotype of both mother and father?
(a) Mother is homozygous for ‘A’ blood group and father is heterozygous for’B’.
(b) Mother is heterozygous for’A’blood group and father is homozygous for’B’.
(c) Both mother and father are heterozygous for’A’and’B’blood group, respectively.
(d) Both mother and father are homozygous for ‘A’ and ‘B’ blood group, respectively.
Answer:
(c) : If mother and father of a person with ‘O’ blood group have ‘A’ and ‘B’ blood group then both mother and father will be heterozygous for ‘A’ and ‘B’ blood group respectively.

Very Short Answer Type Questions

Question 1.
What is the cross between the progeny of F, and the homozygous recessive parent called? How is it useful?
Answer:
The cross between the progeny of F, and the homozygous recessive plant is known as test cross.-This tells about unknown genotype,  i.e., homozygous or heterozygous dominant nature of genotype.

Question 2.
Do you think Mendel’s laws of inheritance would have been different if the characters that he chose were located on the same chromosome?
Answer:
Mendel’s laws of dominance and segregation would have remained the same. Mendel’s law of independent assortment would have been different if the characters that he chose were located on the same chromosome. If the characters are present on the same chromosome they would not assort independently and show linkage.”

Question 3.
Enlist the steps of controlled cross pollination. Would emasculation be needed in a cucurbit plant? Give reasons for your answer.
Answer:
Steps of controlled cross pollination are:

1. Selection of parent
2. Selfing
3. Emasculation
4. Bagging
5. Tagging
6. Artificial pollination
7. Seed setting and harvesting.

Cucurbit plants are generally unisexual plants. So, emasculation cannot be needed. Emasculation is done in bisexual plants to prevent self pollination.

Question 4.
A person has to perform crosses for the purpose of studying inheritance of a few traits/ characters. What should be the criteria for selecting the organisms?
Answer:
The criteria for selecting the organism to study inheritance of characters are as follows:

1. It should be easily available.
2. Shorter life span.
3. Breeding should be cheap and can be done throughout the year.
4. A large number of progeny can be produced.
5. Easily identifiable contrasting characters.

Question 5.
The pedigree chart given below shows a particular trait which is absent in parents but present in the next generation irrespective of sexes. Draw your conclusion on the basis of the pedigree.

Answer:
Given pedigree chart shows autosomal recessive trait. Both parents of generation I are heterozygous (i.e., Hb^A Hb^s) and carrier for the gene. The second and fourth child developed the trait so the genotype is homozygous recessive (i.e., Hb^s Hb^s). The first, third and fifth are carrier for the gene and genotype is heterozygous (i.e., Hb^AHb^s).

Question 6.
In order to obtain the F, generation Mendel pollinated a pure breeding tall plant with a pure breeding dwarf plant. But for getting the F₂ generation, he simply self-pollinated the tall Ft Why?
Answer:
Mendel cross pollinated plants of two different traits of the character of height in order to study their mixing in F1, generation. Only one trait appeared in F1 plants. For knowing the fate of other trait, he allowed the F1 plants to self-pollinate. F₂ generation showed both the traits indicating the recessive trait of the dwarfness remains in F1 generation, but without expresison.

Question 7.
“Genes contain the information that is required to express a particular trait.” Explain.
Answer:
Gene is a unit of inheritance which consists of linear chromosome situated at a specific locus, and carries coded information associated with particular trait. The process of gene expression involves central dogma of genetics e.g., transcription and translation.

Question 8.
How are alleles of particular gene differ from each other? Explain its significance.
Answer:
Allele has a unique nucleotide sequence, it is one of the alternative forms of a gene. In a diploid cell there are usually two alleles of any one gene which occupy the same relative position on homologous chromosomes. These allele may be similar or one allele may be dominant to the other (known as the recessive). It controls the expression of a character.

Question 9.
In a monohybrid cross of plants with red and white flowered plants, Mendel got only red flowered plants. On self-pollinating these F, plants got both red and white flowered plants in 3 : 1 ratio. Explain the basis of using RR and rr symbols to represent the genotype of plants of parental generation.
Answer:

‘R’ represent the dominant character gene whereas V represent the recessive character gene. In F, plants (Rr) both the factors for red and white colour are present. However, the factors for white colour is unable to express itself in the presence of red colour. Hence, the factor for red colour is dominant over the factor for white colour. The factor for white colour is recessive.

Question 10.
For the expression of traits genes provide only the potentiality and the environment provides the opportunity. Comment on the veracity of the statement.
Answer:
The observable characteristics of an organism are determined by its genes, the relationships between the alleles and by the interaction of genes with the environment. Phenotype = Genotype + Environment (Trait) (Potentiality) (Opportunity) Genes can provide only the potentiality and the environment provides the opportunity for the expression of traits. For example a genetically tall plant can become tall only if it receives proper amount of sunlight, minerals and water.

Question 11.
A, B, D are three independently assorting genes with their recessive alleles a, b, d respectively. A cross was made between individuals of Aa bb DD genotype with aa bb dd. Find out the type of genotypes of the offspring produced.
Answer:
The cross between AabbDD and aabbdd and the type of offsprings produced would be:

So, genotypes of offspring produced will be AAbbDd and aabbDd.

Question 12.
In our society a woman is often blamed for not bearing male child. Do you think it is right? Justify.
Answer:
In humans, sex of the child is determined at the time of fertilisation. The female parent produces only one type of egg with X-chromosome. The male gametes are of two types with X-chromosome and Y-chromosome. Fertilisation of the egg with sperm carrying X-chromosome produces a female child while fertilisation with sperm carrying Y-chromosome give rise to male child. Thus sex of the child is determined by male (father) and not by the female (mother).

Question 13.
Discuss the geneticbasisof wrinkled phenotype of pea seed.
Answer:
Seed shape is determined by a single gene, with the allele (R) for round peas domipant over the allele (r) for wrinkled peas (recessive trait). If the alleles for the gene controlling the seed shape are homozygous in a plant, it will show the character or phenotype of the same alleles i.e., RR-Round seed, rr-wrinkled seed. On the other hand, if the alleles of gene are heterozygous, they will express the phenotype of dominant allele. Rr – Round seed (r-wrinkled is recessive). This is the genetic basis of wrinkled phenotype of pea seed.

Question 14.
Even if a character shows multiple allelism, an individual will only have two alleles for that character. Why?
Answer:
Despite multiple allelism, an individual will have only two alleles because an individual develops from a zygote which is the result of fusion of sperm (carrying father set of (n) haploid chromosomes) and an egg (carrying mother set of haploid chromosomes). Sperm and an egg have only one gene (allele) for each trait. Hence an individual will have two alleles despite the occurrence of several alleles in the population.

Question 15.
How does a mutagen induce mutation? Explain with example.
Answer:
Mutagen is an agent that causes an increase in the number of mutants in a population. There are basically two types of mutagens – physical mutagens like UV-rays, gamma rays and chemical mutagens like hydroxyl radicals. Mutagens operate either by causing changes in the DNA of the genes, so interfering with the coding system, or by causing chromosome damage. A mutagen can induce mutation by inducing a change in the base sequence by insertion, deletion or substitution.

Short Answer Type Questions

Question 1.
In a Mendelian monohybrid cross, the F₂ generation shows identical genotypic and phenotypic ratios. What does it tell us about the nature of alleles involved? Justify your answer.
Answer:
In Mirabilis jalapa (Four o’clock) and Antirrhinum majus (Snapdragon or dog flower), there are two types of flower colour in pure state.When the two types of plants are crossed, the hybrid or plants of F1 generation have pink flowers, lithe latter are selfed, the plants of F2 generation are of three types—red, pink and white flowered in the ratio of 1 : 2 : 1 both phenotypically and genotypically. The pink colour apparently appears either due to mixing of red and white colours (incomplete dom inance) oi expression of a single gene for pigmented flower which produces only pink colour (quantitative inheritance).

Question 2.
Can a child have blood group O if his parents have blood group ‘A’ and ‘B’. Explain.
Answer:
A child can have blood group O, if both the parents are heterozygous for their blood groups

Question 3.
What is Down’s syndrome? Give its symptoms and cause. Why is it that the chances of having a child with Down’s syndrome increases if the age of the mother exceeds forty years?
Answer:
Down’s syndrome is a congenital form of mental retardation due to a chromosome defect in which there are three copies of chromosome no. 21 instead of the usual two (i.e., trisomy). The affected individual has a short broad face and slanted eyes (as in the  Mongolian races), short fingers, and weak muscles. Down’s syndrome is caused when the chromosomes of the pair 21 pass into a single egg due to nondisjunction during oogenesis. Then, the egg possesses 24 chromosomes, instead of 23 and offspring has 47 chromosomes instead of 46. The frequency of Down’s syndrome increases, if the age of the mother exceeds forty years. It is due to factors that adversely affect meiotic chromosome behaviour with advancement of women age. In human females, meiosis starts in the foetus to produce egg cells, but it is not completed until after the egg is fertilised. During the long time prior to fertilisation, egg cells are arrested in prophase I. In this suspended state, chromosome may become unpaired. The longer the time in prophase I, the greater the chances for unpairing and chromosome nondisjunction.

Question 4.
How was it concluded that genes are located on chromosomes?
Answer:
The chromosomal theory of inheritance states that the Mendelian factors or genes are located at specific loci on the chromosomes. Occurence of genes over chromosomes was proved by Morgan (1910) during study of sex- linked inheritance of eye colour in Drosophila. It shows criss-cross inheritance, in which female fly passes its X-chromosome and eye colour to male offspring and male fly passes its X-chromosome and eye colour to female offspring.

Question 5.
A plant with red flowers was crossed with another plant with yellow flowers. If F, showed all flowers orange in colour, explain the inheritance.
Answer:
It is the phenomenon of neither of the two alleles being dominant so that expression in the hybrid is intermediate between the expressions of the two alleles in homozygous state. It is called incomplete dominance or intermediate inheritance. There are two types of flower colour in pure state: red and yellow. When the two types of plants are crossed, the hybrid or plants of F, generation have orange flowers. If the latter are selfed, the plants of F₂ generation are of three types – red, orange and yellow flowered in the ratio of 1 : 2 : 1. The orange colour apparently appears due to mixing of red and yellow colours (incomplete dominance).

Question 6.
What are the characteristic features of a true- breeding line?
Answer:
A true breeding line is a pure line that shows same traits, generation after generation due to presence of homozygous characters. They are produced by repeated self fertilisation or breeding between identical homozygous ancestors. They are not superior to high yielding varieties, but are maintained for cross breeding and formation of new varieties.

Question 7.
In peas, tallness is dominant over dwarfness, and red colour of flowers is dominant over the white colour. When a tall plant bearing red flowers was pollinated with a dwarf plant bearing white flowers, the different phenotypic groups were obtained in the progeny in numbers mentioned against them.
Tall, red = 138
Tall, white = 132
Dwarf, red = 136
Dwarf, white = 128
Mention the genotypes of the two parents and of the four offspring types.
Answer:
The result shows four types of offspring with almost similar in number with ratio 1 : 1 : 1 : 1. This kind of result is possible in case of dihybrid test cross. One parent is double hybrid (TtRr) and the other one is double recessive (ttrr).
The test cross can be shown as :

Question 8.
Why is the frequency of red-green colour blindness is many times higher in males than that in the females?
Answer:
Red and green colour blindness is due to X-linked recessive alleles. Males have XY sex chromosomes and presence of single recessive allele expresses itself. Females have XX sex chromosomes. The possibility of female being colour blind is very less because in females both X chromosome should carry the recessive trait, which is very rare due to large scale heterozygosity in human population.

Question 9.
If a father and son are both defective in red- green colour vision, is it likely that the son inherited the trait from his father? Comment.
Answer:
Red and green colour blindness is X-linked character. Colour blindness like any sex-linked trait, shows criss-cross inheritance, i.e., mother transfers traits to her granddaughter through their son, while the father passes traits to her grandson through his daughter. Males have XY type of sex chromosomes, and they get X chromosome from their mother. In this case it is possible that the mother of that male (son) must be a carrier for the character but not affected. Male to male inheritance of X-linked character is not possible.

Question 10.
Discuss why Drosophila has been used extensively for genetical studies.
Answer:
Drosophila is used extensively for genetical studies because of following advantages:

1. It is easily available hovering over ripe mango/banana fruits where it feeds over yeast cells present over the fruit surface.
2. The flies can be reared inside bottles having yeast culture over medium ^:         containing cream of wheat, molasses and agar.
3. A new generation can be raised within 2 weeks with single mating producing hundreds of individuals.
4. The animals can be temporarily inactivated with ether and examined by hand lens/dissection microscope.
5. Female is distinguishable from male by its larger size and ovipositor at the rear end.
6. The animals possess four pairs of chromosomes of different sizes. The male fly possesses XY sex chromosomes while the female has XX chromosomes. Y chromosome is hooked and easily distinguished.
7. Polytene chromosomes occur in salivary glands of larva which can indicate any type of abnormality.
8. Breeding Drosophila is quite cheap. Further, it can be done throughout the year.

Question 11.
How do genes and chromosomes share similarity from the point of view of genetical studies?
Answer:
Similarities of behaviour of chromo-somes with Mendel’s factors / genes.

1. Both pass from generation to generation in altered form.
2. Both are present singly in gametes.
3. An organism receives two genes and two chromosomes of each type from its two parents.
4. Both follows mendelian principles.
5. Each gene and each chromosome replicates during S-phase of cell cycle.

Question 12.
What is recombination? Discuss the applica­tions of recombination from the point of view of genetic engineering?
Answer:
Recombination is the rearrangement of genes that occurs when reproductive cells (gametes) are formed. It results from the I  independent assortment of parental sets of chromosomes and exchange of chromosomal material that occur during meiosis. Useful recombinations produced by crossing over are picked up by breeders to produce useful new varieties of crop plants and animals. Green revolution has been achieved in India due to this selective picking up of useful recombinations operation flood or white revolution is also being carried out on the similar lines. In genetic engineering, the desired genes can be taken from one source and introduce them in the cells of another organism in order to improve and change the same.

Question 13.
What is artificial selection? Do you think it affects the process of natural selection? How?
Answer:
Artificial selection is the modification of species by selective breeding. Animals or plants with desirable characteristics are interbred with the aim of altering the genotype and producing a new strain of the organism for a specific purpose. For example, sheep are bred by means of artificial selection in order to improve wool quality.Yes, it affects the process of natural selection. Natural selection selects trait based on their effect on the fitness of the organism. In artificial selection traits are selected based on human preference for improving traits.The process of natural selection leads to evolutionary change in the expression of the trait in the populations whereas the artificial selection being same process involves the traits preferred by humans for its own benefit. It is much faster than the natural selection, and it impose threat on diversity in long run making it unfit to the natural selected organism.

Question 14.
With the help of an example differentiate between incomplete dominance and co­dominance.
Answer:
Differences between incomplete dominance and codominance are as follows:

Question 15.
It is said, that the harmful alleles get eliminated from population over a period of time, yet sickle cell anaemia is persisting in human population. Why?
Answer:
Harmful alleles become lethal, whenever they occur in homozygous state. The affected individual does not transfer them to the next generation. Over a period of time, these alleles get eliminated from the population. This is not so in the case of sickle cell anaemia. Sickle cell anaemia is an autosomal recessive disorder in which the erythrocytes become sickle shaped under oxygen deficiency as during strenuous exercise and at high altitude.
Despite having harmful effect, the allele for sickle cell anaemia continues to persist in «human population because it has survival value in malaria infested areas like tropical Africa. Malarial parasite is unable to penetrate the erythrocyte membrane and cause any harm. Further, the sickle cell heterozygotes do not always suffer from syndrome. Their erythrocytes appear normal till there is oxygen deficiency when some sickle-shaped erythrocytes may be observed.

Long Answer Type Questions

Question 1.
In a plant tallness is dominant over dwarfness and red flower is dominant over white. Starting with the parents work out a dihybrid cross.What is’standard dihybrid ratio? Do you think the values would deviate if the two genes in question are interacting with each other?
Answer:

Tall red = 9
Tall white = 3 Phenotypic ratio = 9 : 3 : 3 : 1 dwarf red = 3 dwarf white = 1
This is a standard dihybrid phenotypic ratio. Alleles of two or more independent genes interact to produce a phenotypic expression different from the normal expression. They show⁷ dominant epistasis (12 : 3 : 1), recessive epistasis (9:3:4), dominant recessive epistasis (13 : 3) etc.

Question 2.
(a) In humans, males are heterogametic and females are homogametic. Explain. Are there any examples where males are homogametic and females heterogametic?
(b) Also describe as to, who determines the sex of an unborn child? Mention whether temperature has a role in sex determination.
Answer:
(a) Human males are said to be heterogametic because they produce two types of gametes as they have two different sex chromosomes X and Y in addition to autosomes e.g. (A + X) and (A + Y) type of gametes. Whereas human females are homogametic because they produce only one type of gametes, as they have XX sex chromosomes in addition to autosomes (A + X), (A+X). In birds females are heterogametic and have ZW sex chromosomes and males are homogametic with ZZ sex chromosomes.

(b) Sex of unborn child in human is determined by male. Males produce two types of gametes (A + X) and (A + Y). Females produce only one type of gametes (A + X). If (A + X) x (A + X) – female child If (A + X) x (A + Y) – male child Therefore sex of the unborn child completely depends on males. In crocodile and some lizards temperature has a role in sex determination, high temperature induces maleness and low temperature induces femaleness.

Question 3.
A normal visioned woman, whose father is colourblind, marries a normal visioned man. What would be the probability of her sons and daughters to be colour blind? Explain with the help of a pedigree chart.
Answer:
Colour blindness is a recessive sex- linked trait in which eye fails to distinguish red and green colours. The gene for normal vision is dominant. The normal gene and its recessive allele are carried by X-chromosomes. In females, colour blindness appears only when both the sex chromosomes, carry the recessive gene (X^CX^C). The females have normal vision but function as carrier if a single recessive gene for colour blindness is present (XX^C). In males, the defect appears in the presence of a single recessive gene (X^CY) because Y-chromosome of male does not carry any gene for colour vision.Flere, woman is normal visioned, whose father is colour blind, so woman act as carrier because she has got one gene for colour blindness from her father. She marries a normal man, then her 50% daughters will be carrier and 50% will be completely normal. Her 50% sons will be colour blind and 50% will be normal.

Question 4.
Discuss in detail the contributions of Morgan and Sturtevant in the area of genetics.
Answer:
Morgan carried out many dihybrid crosses in Drosophila to study the genes which were sex linked. He hybridised yellow bodied white eyed female to brown bodied red eyed males and intercrossed their F[ progeny. He observed that two genes did not segregate independently and deviated normal F,
ratio 9 : 3 : 3 : 1.
According to him if two genes in a dihybrid cross are situated on same chromosome, the parental gene combinations are much higher than non-parental ones. He gave the term linkage to physical association of genes and recombination to non-parental characters.His students Alfred Sturtevant used the frequency of recombination between gene pairs on the same chromosomes as a measure of distance between genes and mapped their position on the chromosome. The first chromosome maps were prepared by Sturtevant in 1911 for two chromosomes in Drosophila. Genetic maps are extensively used these days as a starting point in sequencing of whole genome in Human Genome Project (HGP).

Question 5.
Define aneuploidy. How is it different from polyploidy? Describe the individuals having following chromosomal abnormalities.
(a) Trisomy of 21^st chromosome
(b) XXY
(c) XO
Answer:
Aneuploidy is the phenomenon of gain or loss of one or more chromosomes that results due to failure of separation of the members of the homologous pairs of chromosomes during meiosis. Polyploidy is a increase of entire set of chromosomes whereas aneuploidy is the addition or deletion of one or few chromosomes from the original genome. Polyploid occurs in nature due to the failure of chromosomes to separate at the time of anaphase either due to non-disjunction or due to nonformation of spindle. Aneuploidy commonly arises due to nondisjunction of the two chromosomes of homologous pair so that one gamete comes to have an extra chromosome (N + 1) while the other becomes deficient in one chromosome (N – 1).
(1) Trisomy of 21^st chromosome :
Trisomy of 21^st chromosome is commonly known as Down’s syndrome. Down’s syndrome is a relatively common birth defect caused by the presence of an extra chromosome number 21 (three instead of two number 21 chromosomes, or, trisomy 21). Both the chromosomes of the pair 21 pass into a single egg due to nondisjunction during oogenesis. This chromosome abnormality adversely affects both the physical and intellectual development of the individual.
The affected individuals have a very different but characteristic external appearance. They display prominent folding at the comer of eyes and have short stature. They have small round head; protruding furrowed tongue that cause the mouth to remain partially open; and short, broad hands with fingers showing characteristic fingerprint patterns. Physical, psychomotor and mental development is retarded and the life expectancy is shortened.

(2) XXY:
An abnormal condition of male sexual characteristics in which the body cells contain one or more extra X-chromosomes. It is caused due to trisomy of sex (X) chromosome. It is known as Klinefelter’s syndrome. Characteristics include undeveloped testicles; long legs and female like breasts. The severity of the abnormalities increases with greater numbers of X-chromosomes. About 30-90 percent of all patients with Klinefelter’s syndrome have the karyotype 47 (2A+XXY). The man may appear generally normal, although infertile.

(3) XO:
It is known as Turner’s syndrome. Individuals having a single X chromosome 2A+XO (45) have female sexual differentiation but ovaries are rudimentary. Other associated phenotypes of this condition are short stature, webbed-neck, broad chest, lack of secondary sexual characteristics and sterility. Thus, any imbalance in the copies of the sex chromosomes may disrupt the genetic information necessary for normal sexual development.

 We hope the NCERT Exemplar Solutions for Class 12 Biology chapter 5 Principles of Inheritance and Variation help you. If you have any query regarding .NCERT Exemplar Solutions for Class 12 Biology chapter 5 Principles of Inheritance and Variation, drop a comment below and we will get back to you at the earliest.

NCERT Exemplar Solutions for Class 12 Biology chapter 4 Reproductive Health

These Solutions are part of NCERT Exemplar Solutions for Class 12 Biology. Here we have given NCERT Exemplar Solutions for Class 12 Biology chapter 4 Reproductive Health

Multiple Choice Questions

Question 1.
The method of directly injecting a sperm into ovum in assisted reproductive technology is called
(a) GIFT
(b) ZIFT
(c) ICSI   
(d) ET.
Answer:
(c) : ICSI or Intra Cytoplasmic Sperm Injection is one of the techniques of Assisted Reproductive Technology (ART) that helps couples to overcome their infertility. In ICSI, sperm is directly injected into ovum, in vitro to form zygote, which is implanted through ZIFT into woman.

Question 2.
Increased IMR and decreased MMR in a population will
(a) cause rapid increase in growth rate
(b) result in decline in growth rate
(c) not cause significant change in growth rate
(d) result in an explosive population/exp.
Answer:
(b) : If there is an increase in infant mortality rate (IMR) and decrease in maternal mortality rate (MMR), mothers are available to give birth to infants but the infants’ survival rate is low, which will ultimately hinder the growth rate of that particular population.

Question 3.
Intensely lactating mothers do not generally conceive due to the
(a) suppression of gonadotropins
(b) hypersecretion of gonadotropins
(c) suppression of gametic transport
(d) suppression of fertilisation.
Answer:
(a) : Presence of prolactin hormone in the blood of lactating mothers suppresses the release of gonadotropins (FSH and LH) from the pituitary gland. Gonadotropins are required for ovulation to occur. Thus, in the absence of, gonadotropins, ovum is not released and hence chances of fertilisation are nil upto 6 months following parturition (if the mother is regularly breast-feeding). Therefore, intensely lactating mothers do not generally conceive.

Question 4.
Sterilisation techniques are generally fool proof methods of contraception with least side effects. Yet, this is the last option for the couples because
(1) it is almost irreversible
(2) of the misconception that it will reduce sexual urge/drive
(3) it is a surgical procedure
(4) of lack of sufficient facilities in many parts of the country
Choose the correct option.
(a) (i) and (iii)
(b) (ii) and (iii)
(c) (ii) and (iv)
(d) (i), (ii), (iii) and (iv)
Answer:
(d) : Sterilisation techniques are surgical procedures where, in males, vas deferens are cut and tied and in females, Fallopian tubes are cut and tied, preventing gamete transport.
Even though it is very effective it is often used as a last option by most couples. One, because it is almost irreversible. Second, because of some misconceptions like absence of ejaculation and lowering of sexual urge.Third, because it is a surgical procedure, there are certain risk of infection. Last but not least,
there are lack of sufficient facilities in many parts of our country (e.g., lack of hygiene, lack of qualified personnel etc.)

Question 5.
A national level approach to build up a reproductively healthy society was taken up in our country in
(a) 1950s
(b) 1960s
(c) 1980s
(d) 1990s
Answer:
(a) : The national level approach towards building a reproductively healthy society began with ‘family planning’ programmes in 1951. Over last 6 decades many other programmes have been started. In 2000, National Population Policy was launched and in 2005, National Rural Health Mission (NRHM) was launched, with the aim of revamping the public health services in rural areas. Janani Suraksha Yojana has also been launched which includes conditional cash transfer. Other improved programmes are also initiated with the term of ‘Reproductive and child Health Care’ (RCH). Launching a number of schemes will benefit only when people are aware of them and those working at the various stages of implementation are doing their work honestly and with right intention.

Question 6.
Emergency contraceptives are effective if used within
(a) 72 hrs of coitus
(b) 72 hrs of ovulation
(c) 72 hrs of menstruation
(d) 72 hrs of implantation.
Answer:
(a)

Question 7.
Choose the right one among the statements given below.
(a) lUDs are generally inserted by the user herself.
(b) lUDs increase phagocytosis reaction in the uterus.
(c) lUDs suppress gametogenesis.
(d) lUDs once inserted need not be replaced.
Answer:
(b) : Copper releasing IUDs (CuT, multiload) increase phagocytosis of sperms within the uterus and the Cu ions released suppress sperm motility and the fertilising capacity of sperms. The hormone releasing IUDs (progestaserf, LNG-20), make the uterus unsuitable for implantation and the cervix hostile to the sperms. IUDs are inserted and removed by trained doctors and they are ideal contraceptives for the females. IUDs, once inserted can be there for a long period of time (even years), especially, copper releasing IUDs. But eventually they need to be removed and replaced, as they are foreign to the body. Fertility returns, once IUDs are removed.

Question 8.
Following statements are given regarding MTP. Choose the correct options given below.
(1) MTPs are generally advised during first trimester.
(2) MTPs are used as a contraceptive method.
(3) MTPs are always surgical.
(4) MTPs require the assistance of qualified medical personnel.
(a) (ii) and (iii)
(b) (i) and (iii)
(c) (i) and (iv)   
(d) (i) and (ii)
Answer:
(c) : Voluntary termination of pregnancy before full term is called Medical Termination of Pregnancy (MTP). It is less riskier during first trimester (upto 12^th week) and requires assistance of qualified medical personnel. Surgical methods of termination of pregnancy include vacuum aspiration of the products of conception through an intra-uterine cannula, etc. It can also be induced using chemical drugs, e.g., mifepristone and prostaglandin. These drugs are taken only in the supervision of qualified medical personnel.

Question 9.
From the sexually transmitted diseases  mentioned below, identify the one which does not specifically affect the sex organs.
(a) Syphilis
(b) AIDS
(c) Gonorrhoea
(d) Genital warts
Answer:
(b) : AIDS (Acquired Immune Deficiency Syndrome) is caused by HIV (Human Immunodeficiency Virus, a retrovirus). It mainly affects the T-helper lymphocytes by infecting them. There is generally a long time lag between infection and occurrence of symptoms. Because of lowering of T-helper lymphocyte count, the person becomes vulnerable to infectious microorganisms, that otherwise, wouldn’t have caused any disease(opportunistic infection). A major example of this is tuberculosis. Weight loss also occurs in such persons.

Question 10.
Condoms are one of the most popular contraceptives because of the following reasons.
(a) These are effective barriers for insemination.
(b) They do not interfere with coital act.
(c) These help in reducing the risk of STDs.
(d) All of the above.
Answer:
(d)

Question 11.
Choose the correct statement regarding the ZIFT procedure.
(a) Ova collected from a female donor are transferred to the Fallopian tube to facilitate zygote formation.
(b) Zygote is collected from a female donor and transferred to the Fallopian tube.
(c) Zygote is collected from a female donor and transferred to the uterus.
(d) Ova collected from a female donor and transferred to the uterus.
Answer:
(None) : In test tube baby programme, ovum from donor female/wife and sperm from donor male/husband are induced to form zygote in the laboratory. The zygote is allowed to divide upto 8 blastomeres in the laboratory. Zygote or early embryo is then transferred into the Fallopian tube. This technique is called ZIFT (Zygote Intra Fallopian Transfer).

Question 12.
The correct surgical procedure as a contracep­tive method is
(a) ovariectomy
(b) hysterectomy
(c) vasectomy
(d) Casttation
Answer:
(c) : Vasectomy is a surgical contracep­tion method performed in males. In vasectomy a small part of the vas deferens is removed or tied up through a small cut on the scrotum.

Question 13.
Diaphragms are contraceptive devices used by the females. Choose the correct option from the statements given below.
(1) They are introduced into the uterus.
(2) They are placed to cover the cervical region.
(3) They act as physical barriers for sperm entry.
(4) They act as spermicidal agents.
(a) (i) and (ii)
(b) (i) and (iii)
(c) (ii) and (iii)
(d) (iii) and (iv)
Answer:
(c) : Diaphragms are soft, hemispherical rubber cups fitted inside the vagina over the neck (cervix) of the uterus acting as physical barrier for sperm entry. When combined with the use of a chemical spermicide, they provide reliable contraception.

Very Short Answer Type Questions

Question 1.
Reproductive health refers only to healthy reproductive functions. Comment.
Answer:
According to WHO (World” Health Organisation), reproductive health means total well being of a person in all aspects of reproduction, i.e. physical, emotional, behavioral and social. It does not only refer to healthy reproductive functions.

Question 2.
Comment on the Reproductive and Child Health Care programme of the government to improve the reproductive health of the people
Answer:
RCH (Reproductive and Child Health Care) Programme aims at improving reproductive health of the society. Various measures undertaken by this programme include creating awareness among people about various reproduction related aspects, providing facilities and support for building up a reproductively healthy society, educating fertile couples about birth control measures, prenatal and postnatal care of mother and child, etc.

Question 3.
The present population growth rate in India is alarming. Suggest ways to check it.
Answer:
Ways to check present population growth rate are:
(1) Educating people by various audiovisual means about the advantages of small families.
(2) Making them aware of ill effects of overpopulation.
(3) Implementing family planning pro­grammes sincerely to achieve zero population growth.
(4) Increasing marriageable age limit.

Question 4.
STDscan be considered as self-invited diseases. Comment.
Answer:
Sexually Transmitted Diseases (STDs) can be considered as self-invited diseases because one could be free of these by following simple precautions. These are as follows:

• Avoid sex with unknown partners/multiple partners.
• Always use condoms during coitus.
• In case of doubt, one should go to a doctor for early detection and complete treatment.

Question 5.
Suggest the reproduction related aspects in which counselling should be provided at the school level.
Answer:
Introduction of sex education in schools is another step to give right information to the young minds about reproductive organs, accessory organs of reproduction, secondary sexual characters, adolescence and related changes, safe and hygienic sexual practices, sexually transmitted diseases, birth control methods etc. This knowledge will save them from myths and misconceptions about sex related aspects.

Question 6.
Mention the primary aim of the “Assisted Reproductive Technology” (ART) programme.
Answer:
ART (Assisted Reproductive Technology) programme assists the infertile couples to have children through some special techniques. It includes various programmes like test tube babies, ZIFT, GIFT, AIT, ICSI etc.

Question 7.
What is the significance of progesterone- estrogen combination as a contraceptive measure?
Answer:
Birth control pills like Mala D and Mala N have progesterone-estrogen combinations, and are commonly called combination pills. They inhibit ovulation and implantation.

Question 8.
Strict conditions are to be followed in medical termination of pregnancy (MTP) procedures. Mention two reasons.
Answer:
Two reasons for following strict condi­tions in medical termination of pregnancy (MTPs) are:

1. It is being misused to abort even the normal female foetuses.
2. MTP performed after first trimester i.e., 12 weeks of pregnancy becomes riskier as foetus becomes more deeply associated with uterine tissue of mother.

Question 9.
Males in whom testes fail to descend to the scrotum are generally infertile. Why?
Answer:
Sperms need slightly lower temperature than body temperature to survive, which is provided by scrotal sac. If testes fail to descend into scrotum, sperms will get killed at high temperature present in abdomen and the person will become infertile.

Question 10.
Mention two advantages of lactational amenorrhea as a contraceptive method.
Answer:
Two advantages of lactational amenorrhea as a contraceptive method are as follows:

1. During intense lactation after parturition, mother does not undergo menstruation and ovulation as high levels of prolactin suppresses ‘ secretion of gonadotropins from anterior pituitary.
2. No medicines or devices are used in this method thus, side effects are almost nil.

Short Answer Type Questions

Question 1.
Suggest some important steps that you would recommend to be taken to improve the reproductive health standards in India.
Answer:
Following measures are needed to be undertaken to improve the reproductive health standards in India :

1. Implementation of RCH (Reproductive and .Child Health Care) and family  planning programmes.
2. To follow child immunisation programme.
3. Introduction of sex education in schools to remove myths and misconceptions about sex related issues.
4. To impose statutory ban on amniocentesis and to check female foeticide.
5. To educate people about various health related programmes and family planning programmes.
6. To control sexually transmitted diseases.
7. Create fertility clinics to diagnose and treat disorders related to infertility.

Question 2.
The procedure of GIFT involves the transfer of female gamete to the Fallopian tube. Can gametes be transferred to the uterus to achieve the same result? Explain.
Answer:
The results will not be the same if gametes are introduced into the uterus, instead of Fallopian tube in the procedure of GIFT. This can be explained as follows. The Fallopian tube and its micro environment are ideal for fertilisation and early embryo development. The anatomy and physiology of Fallopian tube plays an important role in egg transport and fertilisation. Zygote formed as a result of fertilisation, divides to form embryo. Complex interactions take place between oviducal epithelium and the embryo. Human oviducal cells are known to secrete growth factors, cytokines and embryotrophic factors (ETFs) that enhance and support the development of the pre­implantation embryos. On the other hand, the uterine environment is not appropriate for the survival of the gametes, they may undergo degeneration or get phagocytosed in uterus and zygote formation will not be achieved.

Question 3.
Copper ions-releasing lUDs are more efficient than non-medicated methods. Why?
Answer:
Copper releasing IUDs like Cu-T, Cu-7, multi load 375 etc., are more efficient than non- medicated methods because non-medicated methods simply act as barriers for sperm entry into the reproductive tract of female and are not fool proof whereas copper ion releasing IUDs release Cu ions which suppress the sperm motility and fertilising capacity of the sperms and act as better contraceptives.

Question 4.
What are the probable factors that contributed to population explosion in India?
Answer:
Factors favouring population explosion are :

1. Lack of education in developing countries.
2. Lack of entertainment and gainful employ­ment in under-developed countries.
3. Early marriage, child labour.
4. Desire of male child, traditional religious beliefs etc.

Question 5..
Briefly explain IVE and ET. What are the conditions in which these methods are advised?
Answer:
In 1VF (In Vitro Fertilisation), fertilisation takes place outside the body of female in similar conditions as that in the body followed by E.T (Embryo Transfer). It is performed as follows:

1. Ova from the wife/donor female and sperms from husband/donor male are collected in hygienic manner.
2. Both ova and sperms are kept in culture medium under aseptic conditions.
3. Gametes are induced to fuse, and form zygote under simulated conditions.

In ET (Embryo Transfer) technique, developing embryo is transferred from culture medium to female reproductive tract. It is performed as follows:

1. Zygote is induced in culture medium to develop.
2. Endometrium is stimulated to be prepared for implantation.
3. Embryo is transferred to Fallopian tubes in 8 celled condition or transferred to uterus when it is at 16-32 celled stage. When in a woman normal conception is not possible because of blocked oviducts or spermicidal secretions in the vagina or when a woman cannot produce ova or man cannot produce sperms. In such conditions these methods are advised.

Question 6.
What are the advantages of natural methods of contraception over artificial methods?
Answer:
Natural methods of contraception include rhythm method, coitus interruptus and lactational amenorrhea. These methods do not involve use of any contraceptive or any chemical or surgery therefore, do not have any side effects. On the other hand, artificial methods of contraception which include IUDs, oral pills etc., have certain drawbacks. IUDs may cause occasional haemorrhage or infections. Combined oral pills generally have side effects like nausea, breast tenderness, weight gain, breakthrough bleeding and melasma etc.

Question 7.
What are the conditions in which medical termination of pregnancy is advised?
Answer:
The conditions in which medical termination of pregnancy is advised are as follows :

1. To get rid of unwanted pregnancy either due to unprotected intercourse or failure of the contraceptive used or rape.
2. If baby is suffering from an incurable and congenital developmental defect.
3. If continuation of pregnancy is harmful or even fatal either to mother, or to foetus or both.

Question 8.
Comment on the essential features required for an ideal contraceptive.
Answer:
An ideal contraceptive should be:

1. User friendly
2. Easily available and cheaper
3. Effective but also reversible
4. With no or least side effects
5. Should not interfere with the sexual act.

Question 9.
All reproductive tract infections RTIs are STDs, but all STDs are not RTIs. Justify with example.
Answer:
STDs are sexually transmitted diseases and include gonorrhoea, syphilis, genital warts, chlamydiasis, hepatitis B and AIDS. Hepatitis B and AIDS are not RTFs because they do not cause any infection in the reproductive tract but are spread through sexual means, whereas other diseases are STDs as well as RTIs.

Long Answer Type Questions

Question 1.
What are the Assisted Reproductive Techniques practiced to help infertile couples? Describe any three techniques.
Answer:
Assisted reproductive techniques are employed to diagnose and treat the infertile couples to have children. A few techniques are described as follows:

(1) Test tube babies : In this technique the fusion of ovum and sperm is done outside the body of the female to form a zygote Which is allowed to divide to form an embryo. This embryo is- then implanted in the uterus, where it develops into a foetus.

(2) Gamete Intra Fallopian Transfer (GIFT) : This method is vised in females, who can not produce ova, hut can provide suitable environment for fertilisation and further development of embryo in the oviducts. In such cases, ovum from the donor female is introduced into the Fallopian tube of such female. Such women accept sperms from their husbands during copulation.

(3) Intra Cytoplasmic Sperm Injection (ICSI) : It is another specialised technique to form an embryo in laboratory in which a I  sperm is directly injected into the ovum placed in a nutrient broth. The zygote or early embryo is later transferred to the Fallopian tube of woman by ZIFT.

Question 2.
Discuss the mode of action and advantages/disadvantages of hormonal contraceptives.
Answer:
Various hormonal contraceptives are:

1. Hormone releasing IUDs
2. Oral pills
3. Implants
4. Hormone injections

(1) Hormone releasing IUDs – Hormone  releasing IUDs include progestasert and LNG-20. They turn the cervix hostile to spermatozoa and bring changes in  the uterus making it unsuitable for implantation.

(2) Oral pills – They contain progestin  (progesterone like synthetic hormone) alone or a combination of synthetic progesterone and oestrogen. They inhibit the secretion of FSH and LH from anterior pituitary and inhibit ovulation and implantation. They also retard the entry of sperms in the uterus by changing the quality of cervical mucus.

(3) Subcutaneous implants – In this contraception method, six matchstick sized capsules containing synthetic progesterone are inserted under the skin of inner arm above the elbow. It acts similarly to oral contraceptives by blocking ovulation and thickening the cervical mucus to prevent sperm transport.

(4) Hormone injections – These are pro­ gesterone injections which are given once every 3 months and release hormone slowly and prevent ovulation. follows :
Various contraceptive techniques play significant role in checking the uncontrolled growth of human population. They are required to prevent pregnancy.

Disadvantages of hormonal contraceptives are as follows :
These hormone releasing contraceptives especially have many side effects. Use of IUDs possesses the risk of perforation of uterus and infection. Oral contraceptives can cause nausea, weight gain, breast tenderness, breakthrough bleeding, high blood pressure and melasma.

Question 3.
STDs are a threat to reproductive health. Describe any two such diseases and suggest preventive measures.
Answer:
Sexually transmitted disease (STDs) are threat to reproductive health. They are infectious, communicable and acquired diseases. They may lead to various complications like PID (pelvic inflammatory diseases), abortions, still birth, ectopic pregnancies, infertility or even cancer of reproductive tract. Some sexually transmitted diseases are discussed as follows :
(1) AIDS — It is caused by Human Immuno­deficiency Virus (HIV)
Symptoms – Fever, lethargy, pharyngitis, weight loss, nausea, headache, rashes etc.
HIV attacks helper T-lymphocytes. The patient gets immune deficiency and he/ she is unable to protect himself/herself against infections.

(2) Hepatitis B – It is caused by Hepatitis B virus (HBV).
Symptoms – Fatigue, jaundice, persistent low grade fever, rash and abdominal pain. It can also cause cirrhosis and possibly liver cancer.
STDs can be prevented by following ways:

• Use of condoms during coitus.
• Avoiding sex with unknown partners/ multiple partners.
• In case of doubt, consulting a qualified doctor for early detection and getting complete- treatment if diagnosed with disease.

Question 4.
Do you justify the statutory ban on amniocentesis in our country? Give reasons.
Answer:
Amniocentesis (along with sonography) is being misused to determine the sex of the foetus. Due to small family norm, along with religion and social practices, every family wants a male child. The female foetus is destroyed. This has resulted in decline in female population to less than 50 per 100 males in certain areas. Such an imbalance in sex ratio is bound to create social problems for the future generations. Therefore, statutory ban on the test is a rational move.

Question 5.
Enumerate and describe any five reasons for introducing sex education to school-going children.
Answer:
Introduction of sex education is necessary in schools because of the following reasons:

1. ,It will provide correct information about sex related matters and reproductive organs and will help removing all misconceptions and myths.
2. It can explain changes during adolescence. Help can be provided if there is any abnormality.
3. It can predict the changes in behaviour and prevent development of mental problems.
4. It will explain the harms of early sex and early marriage.
5. It will provide proper knowledge of cleanliness of genitalia and other organs.
6. It will provide correct information about sexually transmitted diseases.
7. It will give information about methods of family planning and hygienic sexual practices.

We hope the NCERT Exemplar Solutions for Class 12 Biology chapter 4 Reproductive Health help you. If you have any query regarding .NCERT Exemplar Solutions for Class 12 Biology chapter 4 Reproductive Health, drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 10 Social Science Economics Chapter 2 Sectors of Indian Economy

These Solutions are part of NCERT Solutions for Class 10 Social Science. Here we have given NCERT Solutions for Class 10 Social Science Economics Chapter 2 Sectors of Indian Economy.

TEXTBOOK EXERCISES

Question 1.
Fill in the blanks using the correct option given in the brackets :

1. Employment in the service sector__________ increased to the same extent as production. (has/has not)
2. Workers in the__________ sector do not produce goods. (tertiary/agricultural)
3. Most of the workers in the___________ sector enjoy job security. (organised/unorganised)
4. A_______ proportion of labourers in India are working in the unorganised sector.  (large/small)
5. Cotton is a__________ product and cloth is a____________ (natural/manufactured)
6. The activities in primary, secondary and tertiary sectors are______________ (independent/interdependent)

Answer:

1. has not
2. tertiary
3. organised
4. large
5. natural; manufactured
6. interdependent

Question 2.

1. How the sectors are classified on the basis of ownership of enterprises?
2. What is the secondary sector?
3.  What is GDP?
4. In terms of GDP what was the share of the tertiary sector in 2003?

Answer:

1. Public and Private sector.
2. Production of a commodity, mostly through the natural process is called the secondary sector.
3. GDP is the sum total of the value of all final goods and services of three sectors.
4. Between 50 percent to 60 percent.

Question 3.

1. How the problem of unirrigated land can be solved?
2. How the problem of low prices for crops can be solved? Give one solution.
3. How the debt burden of the farmers can be reduced?
4. How people/farmers can be provided a job in the offseason?
5. “The farmers are compelled to sell their grains to the local traders soon after harvest.” How this can be avoided?

Answer:

1. The problem of unirrigated land can be solved by the construction of canals by the government.
2. This problem can be solved by setting up cooperative marketing societies.
3. The debt burden of the farmers can be reduced by banks by granting credit at low interest.
4. The farmers can be given jobs in the offseason by setting up agro-based mills.
5. This can be avoided by the procurement of foodgrains by the government at a reasonable/ fixed price.

Question 4.
Classify the following workers under their correct sector :
Tourist guide, vegetable vendor, cobbler, Sahara Airlines
Answer:

1. Tourist guide – Organised sector
2. Vegetable vendor – Unorganised sector
3. Cobbler – Service sector
4. Sahara Airlines – Private sector

Question 5.
A research scholar looked at the working people in the city of Surat and found the following :

Complete the table. What is the percentage of workers in the unorganized sector in this
city (in percent) ?                                                                                            ,
Answer:
Complete table is given below :

Question 6.
Do you think the classification of economic activities into primary, second­ary, and tertiary sectors is useful? Explain how.
Answer:
The classification of economic activities into primary, tertiary and secondary is useful on account of the information it provides on how and where the people of a country are employed. also this helps in ascertaining as to which sector of economic activity contributes more or less to the country’s GDP and per capita income.

If the tertiary sector is developing much faster than the primary sector, then it implies that agriculture is depleting, and the government must take measures to rectify this. The knowledge that the agricultural profession is becoming unpopular or regressive can only come if we know which sector it belongs to. Hence it is necessary to classify economic activities into these there sectors for smooth economic administration and development.

Question 7.
For each of the sectors that we came across in this chapter, why should one focus on employment and GDP? Could there be other issues that should be examined? Discuss.
Answer:
For each of the sectors mentioned in this chapter, our focus should definitely be on employment and GDP. This is because growth in GDP and full employment are common goals of Five Year Plans and they also determine the size of a country’s economy. A focus on employment and GDP helps us to calculate and monitor the most important factors like per capita income, productivity, changes in employment rate, and contribution to GDP by the three sectors of the economy and thus, takes necessary steps required for the upliftment of the country’s economy as a whole.
Yes, the other issues which should be examined are

1. balanced regional development
2. equality in income and wealth among the people of the country.
3. how to eradicate poverty
4. modernization of technology
5. self-reliance of the country
6. how to achieve surplus food production in the country.

Question 8.
Make a long list of all kinds of work that you find adults around you doing for a living. In what way can you classify them? Explain your choice.
Answer:
(1) List of working adults: Engineer, doctor, washerman, electrician, shopkeeper, milk vendor, insurance manager, professor, government employee, a zamindar, vegetable seller, domestic help, a factory owner.

(2) Classification of the above kinds of work :

• Primary sector: Zamindar (landowner).
• Secondary sector: Factory owner.
• Tertiary sector: Engineer, doctor, washerman, electrician, shopkeeper, milk vendor, insurance manager, professor, government employee, vegetable vendor, and domestic help.
• Organised sector: Engineer, insurance manager, and doctor.
• Unorganised sector: Washerman, vegetable vendor, milk vendor, shopkeeper, electri­cian and domestic help.
• Public sector: Government employee and professor in a government college.
• Private sector: Engineer and doctor.

Question 9.
How is the tertiary sector different from other sectors? Illustrate with a few examples.
Answer:
The tertiary sector different from other two sectors. This is because other two sectors produce goods but, this sector does not produce goods by itself. But the activities under this sector help in the development of the primary and secondary sectors. These activities are an aid or support for the production process. For example, transport, communication, storage, banking, insurance, trade activities etc. For this reason this sector is also known as service sector.

Question 10.
What do you understand by disguised unemployment? Explain with an example each from the urban and rural areas.
Answer:
(1)

1. Disguised unemployment is a situation in which more people are engaged in an activity than the required ones,
2. This kind of Buder-employment is hidden in contrast to someone who does not have a job and is clearly visible as unemployed.
3. Hence it is also called disguised unemployment,
4. Under disguised unemployment even if the surplus people are removed from work, the production does not suffer.

(2) Rural areas: In rural area in India, more people are employed in agriculture than necessary. Even if you move a few people out, production will not be affected. As such workers in the agricultural sector are underemployed.

(3) Urban areas:

1. The disguised unemployment or under-employment exists in urban areas too. For example, there are thousands of casual workers in the service sector who search for daily employment,
2. They are employed as painters, plumbers and repairpersons and other doing odd jobs,
3. Many of them do not find work every day,
4. Similarly, there are other people of the service sector on the street pushing a cart or selling something who may spend the whole day but earn very little. They do this work because they do not have better opportunities.

Question 11.
Distinguish between open unemployment and disguised unemployment.
Answer:
The differences between open unemployment and disguised unemployment are as mentioned below :

Question 12.
“The tertiary sector is not playing any significant role in the development of Indian economy.” Do you agree? Give reasons in support of your answer.
Answer:
No, I do not agree with the statement that tertiary sector is not playing any significant role in the development of Indian economy. The reasons are as follows:

1. In terms of GDP this sector emerged as the largest producing sector in India surpassing the primary and secondary sectors. In 1973, the share of the tertiary sector in GDP was about 35% which increased to more than 50% in 2003. Over the thirty years between 1973 and 2003, while production in all three sectors increased, it has been the most in tertiary sector.

2. In terms of employment also the rate of growth of employment in tertiary sector between the same period was nearly 250%. This was negligible in primary sector.

Question 13.
Service sector in India employs two different kinds of people. Who are these ?
Answer:
Service sector in India employs two different kinds of people as mentioned below :

1. There are highly skilled and educated workers such as teachers and doctors.
2. On the other hand, a large number of workers are engaged in services such as small shopkeepers, repair persons etc. who barely manage to earn a living. They perform these services because they do not have any other work to do.

Question 14.
Workers are exploited in the unorganised sector. Do you agree with this view ? Give reasons in support of your answer.
Answer:
It is a fact that the workers are exploited in the unorganised sector due to the following reasons :

1. The unorganised sector consists of small and scattered units which are largely outside the control of the government.
2. There are rules and regulations but generally these are not followed by the employers.
3. Workers are employed on irregular basis. They are low paid and there is no provision
   for overtime, paid leave, holidays, leave due to sickness and other facilities e.g., provident fund.
4. Jobs are not secured. They can be asked to leave without any reason at the sweet will of the employer. Generally, when there is less work due to any reason, some workers are asked to leave.
5. Workers in this sector face social discrimination too because most of them belong to Scheduled Castes, Scheduled Tribes and Other Backward Classes.
6. Some workers who do repair work etc. are also exploited as they do not get regular work.
7. Farmers work on their own and hire labourers as and when they require.

Question 15.
How are the activities in the economy classified on the basis of employment conditions?
Answer:
Organised sector and unorganised sector.

Question 16.
Compare the employment conditions prevailing in the organised and unor­ganised sectors.
Answer:
The conditions in the organised and unorganised sectors are as follows :

Question 17.
Explain the objective of implementing the NREGA 2005.
Answer:
The objective of implementing the NREGA 2005 was to provide 100 days of guaranteed employment to those people in rural India who can work, and are in need of work. This Right to Work has been implemented in 200 districts. If the government is unable to provide this employment, then it has to give unemployment allowances to the people.

Question 18.
Using examples from your area compere and contrast the activities and functions of private and public sectors?
Answer:
The activities and functions of private and public sectors in our area may be compared as mentioned below :

Question 19.
Discuss and fill the following table giving one example each from your area :

Answer:

 In the public sector, the services provided by MTNL are better than others and are cheap too. On the other hand, the services provided by the MCD such as sanitation are not satisfactory. Sometimes, the sewers are blocked during rainy season creating health problems in the area.

In the private sector, there are a few private nursing homes and hospitals which provide good medical facilities. But some of the companies such as TPDDL in the private sector have not risen up to the mark. There are still ‘breaks’ in the supply of electricity in the area which cause hardship to the people.

Question 20.
Give a few examples of public sector activities and explain why the govern­ment has taken them up.
Answer:
(1) A few examples of public sector activities are as mentioned below :

• Electricity – production and distribution.
• Selling of food grains – wheat and rice.
• Health and education.
• Safe drinking water.
• Housing facilities for the poor.
• To take care of the poorest and ignored regions.

(2) The government takes up the public sector activities due to the following reasons:

• The modern state is a welfare state which looks after the interests of the people. The government raises money through taxes and other ways and spends on public sector activities for the welfare of the people.
• Selling electricity at the cost of generation may push up the costs of production of industries. Small scale units may shutdown. Therefore government steps in by producing and supplying electricity at rates which these industries can afford. Govt, has to bear part of the cost.
• To have food security in the country, the government of India buys wheat and rice from farmers at a ‘fair price’. These are stored in its godowns and sold at a lower price to consumers through ration shops. The government bears some cost and in this way it supports both farmers and consumers.
• In modern welfare state, it is the responsibility of the government to provide health and education facilities for all citizens. Running proper schools and providing quality education is the duty of the government.
• In India half of children are malnourished. Hence government pays attention to aspects of human development such as availability of safe drinking water, housing facilities for the poor and food and nutrition.
• It is also the duty of the govt, to take care of the poorest and most ignored regions of the country through increased spending in such areas.

Question 21.
Explain, how public sector contributes to the economic development of a nation.
Answer:
Generally, economic development of a nation can be defined as long term increase in per capita income alongwith improvement in quality of life. The public sector contributes to the economic development of a nation in many ways as mentioned below :

• In public sector, the government owns most of the assets and provides services to the people. For example Railways and Post Offices. Railways is the biggest public undertaking. It is very useful for people, traders and industrialists. It is the most dependable mode of transport as it is least affected by weather conditions such as rain, fog compared to other modes of transport. It is better organised than any other form of transport. It is suitable for bulky and heavy goods.
  It is cheaper transport. It is the largest public undertaking. The railways provide greater employment opportunities for both skilled and unskilled labour. Over 16 lakh persons are depending upon railways for their livelihood. Thus it contributes a lot towards the economic development of the country.
• Public sector helps in development through Creation and infrastructure.
• It helps in the development of small, medium and cottage industries.
• It contributes to community development i.e., to the Human Development Index via health and educational facilities.
• It tries to ensure equality of income wealth and thus a balanced regional development.
• It ensures easy availability of goods at moderate rates.
  In India, the public sector has played a significant role in the eradication of illiteracy. The number of literates has increased from 9 per cent of females and 27 per cent of males in 1951 to 75 per cent of males and 54 per cent females in 2001. The government’s efforts in providing health facilities has raised average life expectancy from 32 years in 1950-51 to 61 years in 1993­Thus, we find that public sector contributes to the economic development of a nation in a significant way.

Question 22.
The workers in the unorganised sector need protection on the following issues : wages, safety and health. Explain with examples.
Answer:
(1) Wages: The workers in the unorganised sector do not get minimum wage fixed by the government. They are not paid any allowances like dearness allowance or city compensatory allowance. They are paid only their wages. They are not paid for the extra time, they work in the factory. They do not get any leave or paid holiday.

(2) Safety: No safety measures are taken in the factories for the protection of the workers. This results in injuries or death of labourers in the factory in case of fire or any other accident.

(3) Health: The workers in the unorganised sector are not provided any medical facilities. Whenever they fall ill or get injured, they get themselves treated by private doctors by paying for the treatment. Sometimes the working conditions are not hygienic. They are not paid any medical allowance too. Lack of medical facilities affect their health and efficiency badly.

Question 23.
A study in Ahmedabad found that out of 15,00,000 workers in the city, 11,00,000 worked in the unorganised sector. The total income of the city in this year (1997-98) was ? 60,000 million. Out of this ? 32,000 million was generated in the organised sector. Present this data as a table. What kind of ways should be thought of for generating more employment in the city ?
Answer:
(1) The data is given below as a table :

(2) The following ways or steps should be taken by the government for generating more employment in the city :

1. Electricity should be provided to the factories regularly and at cheap rate especially to the small units. Government should bear part of the cost.
2. Adequate land should be given to people to’set up factories or small units.
3. Financial assistance should be given at less rate of interest.
4.  Raw materials should be made available to the factory owners and other small unit holders.
5. Transport and other facilities should be made’available.

Question 24.
The following table gives you the GDP in Rupees (crore) by the three sectors :

(1) Calculate the share of the three sectors in GDP for 1950 and 2000.
(2) Show the data as a bar diagram similar to Graph 2 in the chapter.
(3) What conclusions can we draw from the bar graph
Answer:
(1) The share of the three sectors in GDP for 1950 and 2000 was as given below :

(2) Share of sectors in GDP is shown in the bar diagram given below :

(3) From the bar diagram the following conclusions can be drawn :

In 1950, the share of primary sector in GDP was more than other sectors. It was 57.97% in comparison to 13.77% and 28.26% of secondary and tertiary sectors respectively.
However in 2000, the share of primary sector decreased from 57.97% to 27.32% while the share of tertiary sector increased from 28.26% to 48.32%. The share of secondary sector too increased from 13.77% in 1950 to 24.36% in 2000

We hope the NCERT Solutions for Class 10 Social Science Economics Chapter 2 Sectors of Indian Economy help you. If you have any query regarding NCERT Solutions for Class 10 Social Science Economics Chapter 2 Sectors of Indian Economy, drop a comment below and we will get back to you at the earliest.