Prasanna

On this page, you will find Nutrition in Animals Class 7 Notes Science Chapter 2 Pdf free download. CBSE NCERT Class 7 Science Notes Chapter 2 Nutrition in Animals will seemingly help them to revise the important concepts in less time.

CBSE Class 7 Science Chapter 2 Notes Nutrition in Animals

Nutrition in Animals Class 7 Notes Understanding the Lesson

1. All organisms including humans require food for growth, repair and functioning of the body.

2. Animal nutrition includes:

• nutrient requirement,
• mode of intake of food and,
• its utilisation in the body.

3. Different organisms have different ways of taking food. For example, snakes swallow their prey, bees and hummingbirds suck nectar from the flowers, etc.

4. The human digestive system consists of the alimentary canal and secretory glands. The canal can be divided into various compartments

• the buccal cavity,
• food pipe or oesophagus,
• stomach,
• small intestine,
• large intestine ending in the rectum and
• the anus.

5. These parts together from the digestive tract.

6. The digestive tract and the associated glands (like salivary gland, liver, pancreas) together constitute the digestive system.

7. Nutrition is a complex process involving

• ingestion,
• digestion,
• absorption,
• assimilation and
• egestion.

The process of taking food into the body is called

8. Digestion is the breakdown of complex components of food into simpler substances.

9. Digestion of food begins in the buccal cavity. Carbohydrate, like starch is digested in buccal cavity. Digestion of protein starts in the stomach.

10. The bile secreted from the liver, pancreatic juice from the pancreas and digestive juice from intestinal wall of small intestine complete the digestion of all components of food in the small intestine.

11. The digested food now passes into the blood vessels in the wall of the intestine. This process is called absorption.

12. The absorbed substances are transported via the blood vessels to different organs of the body where they are used to build complex substances such as the proteins required by the body. This is called

13. The removal of faecal matter through the anus time to time is called

14. Grass-eating animals quickly swallow grass which gets stored in the This partially digested food is called cud. This later returns to the mouth of animals in small lumps, and they chew it. This is called rumination and these animals are known as ruminants.

15. Amoeba ingests its food with the help of finger-like projections, called The food is digested in the food vacuole.

Class 7 Science Chapter 2 Notes Important Terms

Absorption: The passage of the digested food into the blood vessels in the wall of intestine is called absorption.

Amino acid: It is the basic building block of proteins.

Amoeba: It is a single-celled microscopic organism found in pond water.

Assimilation: It is the process in which the absorbed food is used for producing complex substances required by the body.

Bile: Bile juice is a kind of juice secreted by the liver.

Buccal cavity: The cavity of mouth, with all its internal parts like cheeks, teeth, tongue and salivary glands, is called buccal cavity.

Canines: These are two teeth one on each side of the incisors, which help in tearing the food materials.

Cellulose: It is a type of carbohydrate which is present chiefly in all plant tissues and fibres.

Digestion: The breakdown of complex components of food into simpler substances is called digestion.

Egestion: The removal of faeces through the anus from time to time is called egestion.

Fatty acid: It is an organic compound consisting of a long hydrocarbon chain and a terminal carboxylic acid.

Food vacuole: A membrane-bound vacuole (as in an Amoeba) in which ingested food is digested.

Gall bladder: It is a pear-shaped sac, which stores bile juice, and is attached to the undersurface of the right lobe of liver.

Glycerol: It is a colourless, sweet-tasting, viscous liquid, formed as a byproduct when fat is broken down.

Incisors: The front four teeth in each jaw adopted for cutting are called incisors.

Ingestion: The process of intake of food inside the mouth cavity is called ingestion.

Liver: It is a reddish-brown gland located on the upper right side of the abdomen. It secretes bile juice which helps in the digestion of fat.

Milk teeth: The first set of twenty teeth that appears by the age of two is called the set of milk teeth.

Molar: There are six teeth, three on each side of the jaw and just behind the premolars which help in grinding the food materials.

Permanent teeth: Milk teeth are replaced by a set of new teeth, which are thirty two in number, and are called permanent teeth.

Oesophagus: Oesophagus, or food pipe, is a tube-like structure that connect the mouth to the stomach.

Pancreas: It is a large cream-coloured gland located just below the stomach.

Premolar: There are four teeth, two on each side of the jaw which help in crushing the chewed food.

Pseudopodia: One or more finger-like projections in Amoeba which help in movement and ingestion of food is called pseudopodia.

Rumen: Rumen is the first stomach in grass-eating animals, which receives food or cud from the oesophagus immediately after being swallowed.

Ruminant: Animal, that digest food by the process of rumination is called a ruminant.

Rumination: A process by which partially digested food by ruminants returns to their mouth and are again chewed properly, is called rumination.

Salivary glands: Salivary glands are a pair of small and branched structures situated in the mouth cavity. They secrete saliva.

Villi: The inner walls of the small intestine have thousands of finger-like outgrowths called villi.

Saliva: It is a secretion from salivary gland which contains starch splitting enzyme, amylase, for breaking starch into sugar.

On this page, you will find Nutrition in Plants Class 7 Notes Science Chapter 1 Pdf free download. CBSE NCERT Class 7 Science Notes Chapter 1 Nutrition in Plants will seemingly help them to revise the important concepts in less time.

CBSE Class 7 Science Chapter 1 Notes Nutrition in Plants

Nutrition in Plants Class 7 Notes Understanding the Lesson

1. Vitamins, carbohydrates, proteins, fats and minerals are the components of food. These components of food are necessary for our body and are called nutrients.

2. The process of procuring and utilization of food by the body is called nutrition.

3. The mode of nutrition in which organisms make food themselves from simple substances is called autotrophic nutrition.

4. The organisms which cannot make their food and depend on others for their food are called heterotrophs and this type of nutrition is called heterotrophic nutrition.

5. Carbon dioxide from air is taken in through the tiny pores present on the surface of the leaves. These pores are surrounded by ‘guard cells’ such pores are called stomata.

6. The leaves have a green pigment and they are known as chlorophyll.

7. Plants use sunlight, carbon dioxide and water in presence of chlorophyll to synthesise their food. This process is known as photosynthesis.

8. The sun is the ultimate source of energy for all living organisms.

9. The bodies of living organisms are made of tiny units which are called cells.

10. The organisms either plants or animals that derive nutrients from another organisms are known as parasites. For example, Cuscuta, lice, etc.

11. The organisms which provide nutrients to another organisms without being benefitted are known as hosts.

12. The type of plants which trap insects and digest them by producing digestive juices are called insectivorous plants. For example, pitcher plant, sundew, venus fly trap, etc.

13. The mode of nutrition in which organisms take in nutrients in form of solution from dead and decaying matter is called saprophytic nutrition.

14. Plants which use saprophytic mode of nutrition are called saprotrophs.

15. The organisms which live together and share shelter and nutrients are said to be in symbiotic relationship. For example, certain fungi live in the roots of trees.

Class 7 Science Chapter 1 Notes Important Terms

Autotrophic: It is the mode of nutrition in which organisms prepare its own food by using sunlight, air and other essential substances.

Chlorophyll: Chlorophyll is a green pigment present in leaves which absorb solar energy from sunlight, and enables the plant to prepare their food through the process of photosynthesis.

Heterotrophs: The organisms which cannot prepare their food and depends on other organisms for their food are known as heterotrophs.

Host: A plant or an animal which support other organisms by giving food, shelter, etc., is known as host.

Insectivorous: The plant or animal which eat insect for their survival is known as insectivorous.

Nutrients: Vitamins, carbohydrates, proteins, fats and minerals are the components of food. These components of food are essential for our body and are called nutrients.

Parasite: The organism which depends on other organisms for deriving nutrients and their survival is known as parasite.

Photosynthesis: The process by which plants prepare their own food in the presence of sunlight, water, carbon dioxide and chlorophyll is called photosynthesis.

Saprotrophs: Organisms which take their nutrients from dead and decaying matter are called saprotrophs.

Saprotrophic: The mode of nutrition in which an organism take its food from dead and decaying matter is known as saprotrophic mode of nutrition.

Stomata: The tiny pores which are present on the surface of the leaves are called stomata.

In this page, we are providing Wastewater Story Class 7 Extra Questions and Answers Science Chapter 18 pdf download. NCERT Extra Questions for Class 7 Science Chapter 18 Wastewater Story with Answers will help to score more marks in your CBSE Board Exams.

Class 7 Science Chapter 18 Extra Questions and Answers Wastewater Story

Extra Questions for Class 7 Science Chapter 18 Wastewater Story with Answers Solutions

Wastewater Story Class 7 Extra Questions Very Short Answer Type

Question 1.
Define pollutants.
Answer:
The harmful substances which contaminate soil, air and water, etc., are called pollutants.

Question 2.
Name three sources of water.
Answer:

• Lakes
• Ponds
• Wells

Question 3.
Why can’t sea water be used for drinking purpose?
Answer:
Sea water cannot be used for drinking purpose because it contains a big amount of salt that can cause severe water loss and vomiting when consumed.

Question 4.
Why is the bleaching powder mixed with water?
Answer:
Bleaching powder is mixed with water to kill harmful bacteria present in it and make it safe for drinking purposes.

Question 5.
What do you mean by sanitation?
Answer:
Sanitation is the proper disposal of sewage and garbage away from houses and surrounding areas.

Question 6.
Give examples of onsite sewage disposal system.
Answer:
Composting pits, chemical toilets, septic tanks, etc.

Question 7.
Write the full form of WWTP.
Answer:
Waste Water Treatment Plant.

Question 8.
What is meant by chlorination?
Answer:
Chlorination is the process of adding bleaching powder in water to make it safe for drinking.

Question 9.
Give examples of some contaminants present in sewage.
Answer:
Rags, oil, human as well as animal excreta, industrial wastes, etc.

Question 10.
Give examples of some water-borne diseases.
Answer:
Cholera, meningitis, dysentery, typhoid, polio, etc.

Question 11.
Name the type of microbes present in sewage that causes diseases like typhoid and cholera.
Answer:
Bacteria

Question 12.
Name two things that can be made from sludge extracted during treatment of sewage.
Answer:

• Manure
• Biogas

Question 15.
What is scum?
Answer:
Floating dirt or froth on the surface of wastewater is called scum.

Wastewater Story Class 7 Extra Questions Short Answer Type

Question 1.
What is meant by sewerage?
Answer:
Sewerage is a network of big and small pipes called sewage placed under the ground. It can be considered as a transport system that carries wastewater from the point where it is produced to the point of disposal.

Question 2.
Define potable water. Write any two characteristics of potable water.
Answer:
Water that is fit for drinking is called potable water. Its characteristics are following:

• It is odourless and colourless.
• It is transparent.
• It is free from germs and harmful chemicals.

Question 3.
What is clarified water. What can it be used for?
Answer:
Clarified water is the water we get from bar screening, sedimentation, aeration and skimming of the wastewater. It can be used for watering plants, flushing toilets and cleaning public places.

Question 4.
List some sources of water pollution.
Answer:

1. Discharge of sewage
2. Agricultural wastes
3. Domestic wastes
4. Industrial wastes

Question 5.
What should be done to wastewater?
Answer:
Wastewater should not be wasted. It must be cleaned up by removing pollutants.

Question 6.
How do bar screen, and grit and sand removal tank help in cleaning of water?
Answer:
Bar screen removes large objects like rags, cans, plastic packets, etc., from sewage. In grit and sand removal tank heavy solid impurities like pebbles, etc., are removed by sedimentation process.

Question 7.
How does water get polluted?
Answer:
Water is used for numerous purpose in homes, industries, agriculture, etc. It gets polluted when it is used for dying, bathing, flushing toilets, etc. During these activities; many unwanted chemicals, organic and inorganic substances get mixed with water. This pollutes water.

Question 8.
Write one word for the following:
(a) The settled solids that are removed in wastewater treatment with a scraper.
(b) Water from kitchen used for washing dishes.
(c) Wastewater released from homes, industries, hospitals and other public buildings.
Answer:
(a) sludge
(b) wastewater
(c) sewage

Wastewater Story Class 7 Extra Questions Long Answer Type

Question 1.
What is function of a septic tank?
Answer:
A septic tank consists of a big covered underground tank made of concrete. It also consists of an inlet pipe at one end and an outlet pipe at the other end. The toilet seat is connected to the inlet pipe. The human excreta enters the tank through the inlet pipe, the solid portion of the excreta gets collected at the bottom of the tank in the form of sludge whereas the liquid waste gets collected above it.

The anaerobic bacteria break down most of the solid wastes owing to which the volume of solid reduces to a great extent. The liquid waste is also decomposed by the bacteria. Bacteria deposit the digested solid at the bottom of the septic tank. The excess water goes out of the septic tank through the outlet pipe and is absorbed by the soil.

Question 2.
What is vermi-processing toilet? Explain.
Answer:
Vermi-processing toilet is a type of toilet in which the human excreta is processed by earthworms. This has been tested in India. It has proved to be a low-water use, nobel method for disposal of human ex¬creta. Toilet is operated in a very simple and hygienic way. The human excreta is converted into vermi- cakes. Hence it becomes a resource much needed for the soil.

Question 3.
List various steps involved in waste water treatment.
Answer:
Treatment of wastewater involves physical, chemical, and biological processes, which remove physical, chemical and biological matter that contaminates the wastewater.

1. First wastewater is passed through bar screens. Large objects like rags, sticks, cans, plastic packets, napkins are removed.
2. Water than goes to a grit and sand removal tank. The speed of the incoming wastewater is decreased to allow sand, grit and pebbles to settle down.
3. The water is then allowed to settle in a large tank which is sloped towards the middle. Solids like faeces settle at the bottom and are removed with a scraper. This settled solid is called sludge.
4. A skimmer removes the floatable solids like oil and grease. Water so cleared is called clarified water.
5. The sludge is transferred to a separate tank where it is decomposed by the anaerobic bacteria. The biogas produced in the process can be used as fuel or can be used to produce electricity.
6. Air is pumped into the clarified water to help aerobic bacteria to grow. Bacteria consume human waste, food waste, soaps and other unwanted matter still remaining in clarified water.
7. After several hours, the suspended microbes settle at the bottom of the tank as activated sludge. The water is then removed from the top.
8. The activated sludge contains about 97% water which is removed by sand drying beds or machines. Dried sludge is used as manure, returning organic matter and nutrients to the soil.
9. The treated water now, has a very low level of organic material and suspended matter. It is discharged into a sea, or river or into the ground.
10. Nature cleans it up further. Sometimes it may be necessary to disinfect water with chemicals like chlorine and ozone before releasing it into the distribution system.

Question 4.
Name various components of sewage.
Answer:
Sewage is a complex mixture containing suspended solids, organic and inorganic impurities, nutrients, saprotrophic and disease-causing bacteria and other microbes.

1. Organic impurities: Human faeces, animal waste, oil, urea (urine), pesticides, herbicides, fruit and vegetable waste, etc.
2. Inorganic impurities: Nitrates, phosphates, metals.
3. Nutrients: Phosphorus and nitrogen.
4. Bacteria: Such as which causes cholera, typhoid, dysentery, etc.

Question 5.
How can we minimise the discharge of pollutants at their source?
Answer:
To minimise or eliminate waste and pollutants at their source we must see what we are releasing down the drain.

1. Cooking oil and fats should not be thrown down the drain. They can harden and block the pipes. In an open drain the fats clog the soil pores reducing its effectiveness in filtering water. We should throw oil and fats in the dustbin.
2. Chemicals like paints, solvents, insecticides, motor oil, medicines may kill microbes that help purify water. So we should not throw them down the drain.
3. Used tea leaves, solid food remains, soft toys, cotton, sanitary towels, etc. should also be thrown in the dustbin.
4. These wastes choke the drains. They do not allow free flow of oxygen. This hampers the degradation process.

Wastewater Story Class 7 Extra Questions HOTS

Question 1.
What is effluent?
Answer:
Effluent is a liquid waste or sewage discharged into a river or the sea.

Question 2.
State beneficial activity of microbes in sewage disposal.
Answer:
Microbes present in sewage water help to digest organic matter present in it and thus purifying water aerobically. Anaerobic microbes help in digestion of sludge into useful manures.

Question 3.
What are the common symptoms of water-borne diseases?
Answer:
Common symptoms of water-borne diseases are vomiting, stomachache, diarrhoea, fever, loss of appetite, etc.

Question 4.
How the terms sewage, sewers and sewerage are interlinked to each other?
Answer:
Sewage is the wastewater coming from houses and other places. Sewers are the pipes which carry sewage whereas network of sewers, manholes, pumping stations, drains, etc. form sewerage.

Question 5.
Why should we not throw
(a) Cooking oils and fats down the drains?
(b) Cotton buds, napkins and nappies down the toilets?
Answer:
(a) Cooking oils and fats can harden and block the pipes.
(b) Cotton buds, napkins and nappies are flushed with difficulties and are not easily degradable. They can block the drains.

Wastewater Story Class 7 Extra Questions Value Based (VBQs)

Question 1.
Sonam never mind to dispose her household waste like tea leaves, vegetable peels and even remaining foods from plates into the sink. Sometimes she even flush the waste from brooming or sweeping into the toilets.
(a) What will be the affects of Sonam’s practices on the process of wastewater treatment?
(b) How Sonam’s practice of throwing waste into sink and toilets will affect the sewer system?
(c) What value of Sonam is shown here?
(d) Being an active citizen, what would you like to suggest Sonam?

Answer:
(a) She is adding to the load of WWTP, by increasing waste and pollutants at their source.
(b) Throwing of tea leaves, vegetable peels and food remains may clog the sewer pipes. Waste from brooming and sweeping may also contain some non-biodegradable wastes which can choke drains or hamper in degradation processes.
(c) Sonam is impulsive, irresponsible and eco-unfriendly.
(d) Sonam must throw all the solid waste into a dustbin instead of throwing directly into sink or toilet. She must minimise or eliminate waste and pollutants at their source to decrease the load on WWTP.

In this page, we are providing Food Where Does it Come From Forests: Our Lifeline Class 7 Extra Questions and Answers Science Chapter 17 pdf download. NCERT Extra Questions for Class 7 Science Chapter 17 Forests: Our Lifeline with Answers will help to score more marks in your CBSE Board Exams.

Class 7 Science Chapter 17 Extra Questions and Answers Forests: Our Lifeline

Extra Questions for Class 7 Science Chapter 17 Forests: Our Lifeline with Answers Solutions

Forests: Our Lifeline Class 7 Extra Questions Very Short Answer Type

Question 1.
Give four examples of forest animals.
Answer:
Tiger, lion, elephant, bear, etc.

Question 2.
What is meant by canopy?
Answer:
The branches of tall trees look like a roof over the other plants in the forest is called canopy.

Question 3.
Why do trees vary from place to place in their shapes and sizes?
Answer:
Because of different climatic conditions.

Question 4.
Define carnivores.
Answer:
The organisms which eat flesh and are dependent on other animals for food are called carnivores.

Question 5.
Define herbivores.
Answer:
The organisms which depend on plants or plant products for their food are called herbivores.

Question 6.
Give three examples of herbivores.
Answer:
Deer, elephant, rabbit.

Question 7.
How can the presence of an animal be recognised in the forest?
Answer:
By its droppings and footprints.

Question 8.
Define food web.
Answer:
Several interrelated food chains or feeding relationship among organism in an ecosystem is called food web.

Forests: Our Lifeline Class 7 Extra Questions Short Answer Type

Question 1.
Differentiate between autotrophs and heterotrophs.
or
Differentiate between producer and consumer.
Answer:

Question 2.
Give an example of food chain.
Answer:
Grass is eaten by insects, which in turn, is taken by the frog. The frog is consumed by snakes. This is an example of food chain.

Question 3.
Name any four birds which you expect to see in a forest.
Answer:
Kingfisher, blue jay, hornbill and jungle crow.

Question 4.
How does the forests floor look like?
Answer:
The forest floor looks dark-coloured and covered with a layer of dead and decaying fruits, plants, leaves, twigs and small herbs, which is quite moist and warm.

Question 5.
What do you mean by deforestation? Give some causes of deforestation.
Answer:
The excessive cutting of trees for personal or commercial purposes is called deforestation.
Two causes of deforestation are as follows:

1. Land is required to be cleared for cultivation, construction of houses, road, etc.
2. Forest fires cause huge loss to forest cover which may be natural or by man.
3. Overpopulation too directly affects forest covers with the expansion of his habitat.
4. Felling of trees recklessly for obtaining timber also causes deforestation.

Question 6.
What is the importance of dense bushes and tall grasses for animals living in the forests?
Answer:
The dense bushes and tall grasses provide the animals with food and shelter. Moreover, they protect the herbivores from carnivores living in the forest.

Question 7.
Why is it dark inside a forest?
Answer:
It is dark inside the forest because sun rays are hardly able to penetrate through the dense covering of leaves. The canopy of tall trees form a roof over the other plants. The trees also get covered with different types of creepers and climbers.

Question 8.
How does photosynthesis and respiration maintain the 02-C02 balance in the atmosphere?
Answer:
Photosynthesis is the process in which carbon dioxide gas is used and as a byproduct oxygen is given out. This oxygen is used by the animals for respiration and carbon dioxide is given out which is again used by green plants for photosynthesis.

Question 9.
How do forests help in bringing rain?
Answer:
Trees absorbs water from the soil through their roots, and the excess water is released in the atmosphere through transpiration in the form of water vapour. This released water vapour forms clouds which later bring rainfall.

Question 10.
Why are forests called green lungs?
Answer:
Forests, like lungs, maintain the 02-C02 balance in the atmosphere. Therefore forests are called green lungs.

Forests: Our Lifeline Class 7 Extra Questions Long Answer Type

Question 1.
Write the importance of forests.
or
Why forests are also known as our ‘lifeline’?
Answer:
The major importance of forests are following:

1. They maintain the 02-C02 balance in the atmosphere.
2. They maintain ground water level.
3. They prevent the soil from getting eroded.
4. They provide us with food, shelter, medicines, timber, wood and other useful products.
5. They maintain water cycle in the nature.

Question 2.
How does forests sustain a large variety of animals?
Answer:
Different types of animals live in the forest, like herbivores, carnivores, scavengers, etc. Forest provides them with suitable living conditions. The animals get their food in the forest itself. Herbivores feed on plants. Carnivores eat herbivores and thus survive. When these animals die, various scavengers like vultures, eagles, etc., feed on their dead bodies.

Numerous microorganisms also live in the forest that convert dead and decaying plant and animal tissues into humus. They are called decomposers. Thus, they provide a hostile condition for all the animals.

Question 3.
How do forests prevent soil erosion? Explain.
Answer:
The removal of top layer of fertile soil by the action of wind, river or rain is known as soil erosion. This can change a fertile land into a desert. This happens in areas which are not covered with vegetation like trees and plants.

The roots of plants and trees bind the soil particles together firmly. Owing to this, strong winds and flowing rivers find it very difficult to take away the particles of soil. In this way soil erosion is prevented.

When it rains heavily in a forests, the rainwater is first intercepted by the canopy and then it comes down through stem, branches and leaves of the forest plants. Over this process the speed of the rainwater slows down. In this way, the rainwater does not hit the floor of the forest directly. The forest floor covered with fallen, leaves and twigs absorbs water readily and do not allow it to flow and thus, also prevent soil erosion.

Question 4.
As an active citizen, elaborate your role in protecting the forests?
Answer:
At my level I will do the following things to protect the forest:

1. Use less paper and try to recycle it.
2. Do not buy any products made up of or obtained from killing of wild animals.
3. Try to plant as many trees as I can.
4. Aware people about the importance of forest in our lives.
5. Reduce use of artificial items as it also create stress on the forest.

Forests: Our Lifeline Class 7 Extra Questions HOTS

Question 1.
How do trees grow in the forest without human interference? Explain.
Answer:
Forest is a self-sustaining system. Forest floor is fertile due to presence of humus. Various agents like animals, wind, water, etc., disperse the seeds of many plants. When these seeds get the favourable conditions, like nutrient, water and proper temperature germinate into a seedling and gradually into a plant. Thus, no human interference is required for trees to grow in a forest.

Question 2.
Explain why a forest is called a ‘dynamic living entity’.
Answer:
Forests are called dynamic living entity because of the various plants, animals and microorganisms. The wide variety of animals helps the forest to regenerate and grow. Decomposers help in maintaining the supply of nutrients to the growing plants in the forest. Thus, in a nutshell forest is a dynamic living entity, full of life and vitality.

Question 3.
How do you think a bunch of seedlings sprouting on a heap of animal dropping in a forest will be benefitted?
Answer:
The decaying animal dropping will provide nutrients to the growing seedlings.

Question 4.
It is a matter of concern if any plants or animals perish from forest. Explain, why?
Answer:
Every component of a forest is dependent on other. If any of these component perish due to any adverse condition all other components of the forest get affected. For example, if herbivores are eliminated from the forest, then the forest will grow very dense due to no one to eat them and the carnivores will perish due to unavailability of food.

Forests: Our Lifeline Class 7 Extra Questions Value Based (VBQs)

Question 1.
Somya likes to buy books and copies. To finish a copy she wastes a lot of space and leave most of the pages blank. When she finds that her book shelf is full with old copies and books she just throw then in the dustbin. Once her cousin Abhishek visited her home. On seeing such a wastage of papers he said to her that this practice of hers is actually the cause of deforestation and she must stop this immediately.
(a) How wasting of papers are the cause of deforestation?
(b) How can we save papers?
(c) What value of Somya is shown here?

Answer:
(a) Papers are obtained from tree fibres. Making of papers causes felling of trees on a large scale. So wasting of papers mean making more papers which cause deforestation.
(b) We can save papers by following ways:

1. By recycling papers and using recycled papers.
2. By writing on both sides of papers.
3. By using all the space available on the paper.
4. By using paperless technologies like using phone or email to communicate, etc.

(c) Somya is passionate of buying books and copies without their requirement, extravagant, eco-unfriendly and immature.

In this page, we are providing Water: A Precious Resource Class 7 Extra Questions and Answers Science Chapter 16 pdf download. NCERT Extra Questions for Class 7 Science Chapter 16 Water: A Precious Resource with Answers will help to score more marks in your CBSE Board Exams.

Class 7 Science Chapter 16 Extra Questions and Answers Water: A Precious Resource

Extra Questions for Class 7 Science Chapter 16 Water: A Precious Resource with Answers Solutions

Water: A Precious Resource Class 7 Extra Questions Very Short Answer Type

Question 1.
What message do we get from water day?
Answer:
We celebrate water day to attract the attention of everybody towards the importance of conserving water.

Question 2.
What percentage of earth’s surface is covered with water?
Answer:
71%.

Question 3.
What is the two sources through which groundwater gets recharged?
Answer:
The rainwater and water from other sources such as rivers and ponds are the sources for recharging groundwater.

Question 4.
What will happen to plants if they do not get water for few days?
Answer:
Plants will wilt and ultimately dry-up if they are not watered for a few days.

Question 5.
List the main sources of underground water.
Answer:
Springs, tubewells, handpumps, etc.

Question 6.
What is water management?
Answer:
Minimum wastage of water is called water management.

Question 7.
Name the techniques of watering plants which minimises the wastage of water.
Answer:
Drip irrigation.

Question 8.
Why do certain regions on the earth become desert?
Answer:
Certain regions on the earth became desert because they got very little rain.

Question 9.
What is the minimum amount of water per person per day recommended by United Nations?
Answer:
50 Litres.

Question 10.
State any one way to prevent the wastage of water.
Answer:
There should not be any leakage in the supply lines.

Water: A Precious Resource Class 7 Extra Questions Short Answer Type

Question 1.
Define briefly what is water cycle.
Answer:
The continuous movement of water from the water bodies to the atmosphere and again back to the water bodies is called water cycle.

Question 2.
What do you mean by surface water?
Answer:
The water present on the surface of the earth is called the surface water.

Question 3.
What do you mean by rainwater harvesting?
Answer:
Collecting and conserving the rainwater from the roof tops of the buildings is called rainwater harvesting.

Question 4.
How is water table maintained below the earth?
Answer:
The rainwater and water from other sources seeping into the earth maintains the water table. This is called replenishing the water table.

Question 5.
What is the reason due to which earth appear blue from space?
Answer:
The earth appears blue from space because a major part of the surface of earth is covered with water in seas and oceAnswer:It is this water on the earth which makes it appear blue in colour.

Question 6.
What is drip irrigation?
Answer:
Drip irrigation is a technique of watering the plants by making use of narrow tubings which deliver water drop by drop directly at the base of the plant.

Question 7.
What is freshwater?
Answer:
The water that is fit for human consumption is called freshwater.

Question 8.
List the various reasons of depletion of water table.
Answer:
Following are the various reasons for depletion of water table:

1. Increase in population
2. Scanty rainfall
3. Deforestation
4. Agricultural activities
5. Industrialization
6. Decrease in the effective area of seepage of water.

Question 9.
What are bawris?
Answer:
Bawris are the old age practices of water storage and water recharge. It is a step well in which a person can go down by using set of steps to fetch water.

Water: A Precious Resource Class 7 Extra Questions Long Answer Type

Question 1.
What do you mean by conservation of water? How can we conserve water?
Answer:
The process of conservation of water is the wise and judicious use of water by us. We can conserve water by different ways. Rainwater harvesting minimises the wastage of water in houses and industries, us¬ing conservation techniques like drip irrigation in agriculture, etc., are few methods of conservation of water.

Question 2.
Explain briefly what is rainwater harvesting?
Answer:
Collecting and conserving the rainwater from the roof tops of the buildings is called rainwater harvesting. Water from the roof tops of the houses, industries, etc., is collected. It is used directly or allowed to seep into the soil instead of allowing it to flow down. It helps in raising the water table.

Question 3.
List five advantages of conserving water.
Answer:
Following are the five advantages of conserving water:

1. Protects drinking water resources.
2. It solves the problem of water scarcity.
3. It helps to recharge groundwater.
4. It saves energy and money.
5. It save freshwater to run off into sea and ocean.

Question 4.
Explain how increasing population is responsible for the depletion of water table.
Answer:
Increasing population creates demands for construction of houses, shops, offices, roads and pavements. This decreases the open areas like parks and playgrounds. This in turn decreases the seepage of rainwater into the ground.

Moreover a huge amount of water is required for construction work and daily chores, often groundwater is used for this purpose. So on the one hand we are consuming more groundwater and on the other we are allowing lesser water to seep into the ground. This results in depletion of water table. In fact, the water table in some parts of many cities has gone down to alarmingly low levels.

Question 5.
How can you contribute towards water conservation?
Answer:
We can contribute towards water conservation by
(a) checking faucets and pipes for leaks.
(b) turning off taps while brushing
(c) mopping the floor instead of washing.
(d) using water after mopping to water the plants.
(e) using grey water from washing machine to flush the toilets.
(f) watering plants in evening and morning to avoid loss of water due to evaporation.

Water: A Precious Resource Class 7 Extra Questions HOTS

Question 1.
What is the source of water in each of the following?
(a) Wells
(b) Atmosphere
(c) Ground
Answer:
(a) Groundwater
(b) Evaporation (from ponds, lakes, transpiration, etc.)
(c) Rain (through infiltration)

Question 2.
Three-fourths of earth is covered with water, then why we need to conserve water?
Answer:
Seas and oceans occupy a vast per cent of water and is salty. This water is unfit for human consumption. Only a little per cent of water is freshwater. Out of this freshwater major portion is present in the frozen form in glaciers, ice caps and permanent snow. Thus, only a little is present as groundwater and much lesser than that as ponds, lakes, rivers, etc. So for our future we need to conserve water.

Question 3.
How scarcity of water can effect education of children?
Answer:
In water scarce area, children cannot attend school regularly since they spend hours in fetching water. Also, many children are not able to attend the school due to water-borne diseases caused due to absence of safe drinking water.

Question 4.
How scarcity of water can effect health as well as economy of an area?
Answer:
Water scarcity will force people to drink contaminated or polluted water. It may also lead to unhygienic conditions as our daily activities need lot of water to keep us clean. Thus, can lead to many infectious diseases. Neither small businesses or major global industries can function properly without water. Also, unhealthy people cannot work properly or able to attend a business. Thus, water scarcity effects health as well as economy of an area.

Water: A Precious Resource Class 7 Extra Questions Value Based (VBQs)

Question 1.
A bottle packaging company established in Rohan’s village started extracting a large quantities of water from the ground. It affected both the quantity and quality of water. All the wells in their village dried up. Women now had to walk nearly five kilometres to fetch water. All the villagers united to protest against the packaging company and led to its permanent closure.
(a) Why the wells in village dried up?
(b) How the quality of groundwater deteriorates due to over-extraction?
(c) How can groundwater be replenished again?
(d) What value of villagers are shown here?

Answer:
(a) Wells in the village dried up due to over-exploitation of groundwater by the packaged drinking water company.
(b) Excessive pumping in coastal areas cause saltwater to move inland and upward, resulting in saltwater contamination of the water supply.
(c) Groundwater can be replenished again through rainwater harvesting by building bunds, check- dams and other methods which helps in much percolation of water into the ground. By planting more and more trees, i.e., reforestation, groundwater level can be increased.
(d) Villagers are conscious of their rights and duty to mother nature, and united.

Question 2.
Water is one of the most important compound for all living things. There can be no life without it. Empty water pots, long queue of women and children, people jostling to get a bucket of water when a tanker arrives, etc., are common scenes at the onset of summer or in water-scarce area. Still many people who are blessed with this precious gift, water, do not bother to waste it thoughtlessly.
(a) Do you think that handling the most precious gift of nature thoughtlessly is correct?
(b) In your level how would you try to minimise the wastage of water?
(c) Write two slogans for conserving water.

Answer:
(a) No.
(b)

1. Close the tap while brushing.
2. Check for leaking taps and water pipes.
3. Use water from mopping for watering plants
4. Help in spreading water education and creating awareness amongst the masses.

(c)

1. Water water everywhere, try to save it if you care’.
2. ‘Slow the; flow, save H20’.