STD - 3, CHAPTER 10 - WATER, EXTRA QUESTIONS AND ANSWERS

1.      Mention any four activities where we use water.

Ans: Water is used for,

i)  Bathing

ii) Cooking

iii) Watering plants

iv) Cleaning purposes

2.      What are sources of water?

Ans: The places from where we get water, are called as the sources of water.

3.      Name some sources of water.

Ans: Some sources of water are rain, snow, lakes, ponds, wells, rivers, seas and oceans.

4.      Name two main natural sources of water.

Ans: Rain and snow are two main natural sources of water.

5.      Name any three inland water bodies. (OR) Name any three local sources of water.

Ans: Three inland water bodies are, lakes, ponds and rivers.

6.      From where do the rivers, lakes, ponds and wells get water?

Ans: Rivers, lakes, ponds and wells mainly get water from rain and snow.

7.      Why are picnic spots often developed around or near lakes?

Ans: Water present in the lakes is used for boating and other water-sports. So, picnic spots are often developed around or near lakes.

8.      Why rain is called as the most important natural source of water?

(OR) How rain helps in filling other water bodies?

Ans: i) Lakes, ponds and rivers get water mainly from rain.

ii) The rivers flow into a sea or an ocean.

iii) A part of the rain water goes underground.

Thus, rain is the main natural source of water.

9.      Define “ground water”.

Ans: Water, present under the surface of earth, is called ground water.

10.  How is ground water useful?

Ans: i) Ground water is used by plants for their growth.

ii) People also draw ground water and use it for different purposes.

11.   State two methods of drawing ground water.

Ans: Ground water can be drawn from the wells and by using hand pumps.

12.  Write any two importance of rain water.

Ans: i) Rain water helps in filling the other water bodies.

ii) Rain water is a natural source of irrigation for plants and crops.

13.  Why do plants look greener after rain?

Ans: Rain water washes away the dust and dust from the leaves of the plants. So, plants look greener, fresh and more beautiful after a rainfall.

14.  Name the bird which dances merrily in rain.

Ans: Peacock dances merrily in rain.

15.  Why the peacock dances in rain?

Ans: The peacock dances in rain as it enjoys the rain and feels happy.

16.  When do the mountains get a heavy snowfall?

Ans: In winters, the mountains get a heavy snowfall.

17.  How is snow a source of water?

Ans:i) During summer, when the snow melts, it changes into water.

ii) This water flows down the mountains into rivers and lakes.

Thus, snow is a source of water.

18.  Write some places which are located on the bank of a river. Also name the rivers.

PLACE	RIVER
Kolkata	Hooghly
Cuttack	Mahanadi
Patna, Kanpur, Haridwar, Varanasi	Ganga
Nasik	Godavari

 

     

 

 

19.  Name the longest river of the world.

Ans: The longest river of the world is the Nile in Egypt.

20.  Name the major rivers of North India.

Ans: The major rivers of North India are Indus, Brahmaputra, Ganga, Yamuna, Satluj, Beas and Chenab.

21.   Name the major rivers of South India.

Ans: The major rivers of South India are, Krishna, Cauvery, Godavari, Mahanadi, Narmada and Tapi.

22.  Name the water bodies surrounding India on its three sides.

Ans: India is surrounded by the Indian Ocean, Bay of Bengal and the Arabian sea, on its three sides.

23.  Name the five oceans of the world.

Ans: The five oceans of the world are, i) Pacific Ocean

ii)     Atlantic Ocean

iii)   Indian Ocean

iv)   Southern Ocean

v)     Arctic Ocean

24.  Name the water body present on the southern side of India.

Ans: The Indian Ocean is present on the southern side of India.

25.  Name the water body present on the Eastern side of India.

Ans: Bay of Bengal is present on the east side of India.

26.  Name the water body present on the western side of India.

Ans: The Arabian sea is present on the western side of India.

27.  Write one use of water in the canals.

Ans: Water in canals is used for irrigating the fields.

28.  Define “Irrigation”.

Ans: Watering the crops is called as irrigation.

29.  Define “Hydro-electricity”.

Ans: The electricity generated by using water, is called hydro-electricity.

30.  Define a dam.

Ans: A place where a large amount of river water is stored, is called a dam.

31.  How is a dam useful for generating electricity?

Ans: i) A dam stores river water in it.

ii) This stored water can be used to generate electricity.

iii) For this, the water is made to fall from a height.

32.  Name four dams in India. Also mention the state in which they are built.

Name of Dam	State	River
Tunga Bhadra Dam	Karnataka	Tungabhadra River
Gandhi Sagar Dam	Madhya pradesh	Chambal river
Gangapur Dam	Maharashtra	Godavari river
Hirakud Dam	Odisha	Mahanadi river
Govind Ballabh Pant Sagar	Uttar Pradesh	Rihand river
Tehri Dam	Uttarakhand	Bhagirathi River

STD - 4, CHAPTER 8 - Water Scarcity and Conservation of Water, EXTRA QUESTIONS AND ANSWERS

 

1.      How much of the surface of earth is covered by water?

Ans: Three-fourth of the surface of earth is covered by water.

2.      Why is Earth called a blue planet?

Ans: The Earth is called a blue planet, because three-fourth of its surface is covered with water.

3.      Why the ocean water cannot be used for our daily needs?

Ans: Ocean water cannot be used for our daily needs, because ocean water is salty.

4.      Name three sources of fresh water.

Ans: Rivers, streams and lakes are the sources of fresh water.

5.      ‘Three-fourth of the surface of earth is covered by water. Still, there is a scarcity of water.’ Give reason.

Ans: i) Most of the water exists in oceans, which is salty.

ii) Only a small part of water is fresh water. Amount of fresh water is further decreasing due to various factors.

Hence, there is a scarcity of water.

6.      State three factors that are responsible for water scarcity.

Ans: Three factors that are responsible for water scarcity are, i) Population

                                                                                                              ii) Deforestation and

                                                                                                             iii) Setting-up of factories.

7.      How does increase in population lead to water scarcity?

Ans: i) With increase in population, the demand for water has also increased.

ii) More people need more water, but the supply is not increasing.

Thus, it leads to scarcity of water.

8.      Name the two main natural sources of water.

Ans: Rain and snow are the two main natural sources of water.

9.      What is deforestation?

Ans: Cutting of trees in more numbers is called deforestation.

10.  State two reasons that are leading to clearing of forests.

Ans: i) Forests are being cleared, for building houses and factories.

ii) Also, people cut trees for earning money by selling the wood of trees.

11.  State the effect of deforestation on rainfall.

Ans: Deforestation results in a decrease in rainfall.

12.  How can we bring balance in nature?

Ans:i) We can bring balance in nature by taking strict steps to prevent deforestation.

ii) More and more trees need to be planted to maintain the balance in nature.

13.  How does setting-up of factories affect the ground water level?

Ans:  i) The factories need a large quantity of water. So, they use underground water.

ii) Due to shortage of rainfall, underground water does not get filled up again as much as it is used.

iii) This has led to a sharp decrease in the level of underground water.

14.  What is the need to save water?

Ans: i) If we continue to waste water resources carelessly, a time will come when there will not be enough water for all of us.

ii) The crops can also die due to lack of irrigation.

So, there is a need to save water now, so that it remains available for use in future also.

15.  What is water conservation?

Ans: Proper and careful utilisation of water, avoiding its wastage, and maintaining the amount of water in its different sources, is called water conservation.

16.  State the different ways of conserving water at home.

Ans: We can conserve water at home by adopting the following measures.

i) Turn off the tap after using it.

ii) Do not keep the tap running while brushing teeth or washing hands.

iii) Use a mug and bucket to take bath instead of a shower.

iv) Water the plants with a bucket and mug instead of a pipe.

v) Take only that much water in a tumbler that you can drink. Do not throw the leftover water in the sink. Pour it over plants.

vi) Do not throw away water used for washing vegetables, rice or pulses. Use it for watering plants.

vii) Get the leaking pipes and taps repaired immediately.

17.  How should the fields be irrigated toreduce wastage of water?

Ans: i) Over-irrigation of fields should be checked.

ii) Water sprinkler should be used for irrigation. This reduces the wastage of water.

18.  State the utilities of dams.

Ans: i) Dams preserve a large quantity of water.

ii) Dams also check floods.

19.  What is rain water harvesting?

Ans: Collecting rain water for day-to-day use, is called rain water harvesting.

20.  State two ways to do rain-water harvesting.

Ans: i) Rain water can be collected in large underground tanks from where it seeps slowly into the ground.

ii) Rain water may also be collected in overhead tanks and used for daily needs.

21.  How can we increase the level of underground water?

Ans: By collecting rain water in large underground tanks from where it seeps slowly into the ground, we can increase the underground water.

STD 5 CHAPTER 4 - ANIMALS - OUR FRIENDS, EXTRA QUESTIONS AND ANSWERS

 

1.      Explain the usefulness of animals in our day-to-day life.

Ans: The following points explain the usefulness of animals in our day-to-day life:

i)          Silk and wool that are used for making cloth, come from silkworm and sheep respectively.

ii)        Leather, obtained from the skin of animals like goat, sheep and buffalo, is used to make shoes, purses and bags.

iii)      Pearls, are obtained from oysters.

iv)      Many types of fish, prawns, lobsters and crabs, are used as sea food.

v)        Animals like horses, camels, elephants are used as means of transport.

vi)      In the ancient times, kings had dogs that used to assist them in hunting in the forests. At present, dogs assist police in various search operations.

vii)    Animal waste, like cowdung, is converted to compost. Compost makes soil fertile for growth of plants.

2.      Name the animal that gives us silk.

Ans: Silkworm gives us silk.

3.      Name the animal that gives us wool.

Ans: Sheep gives us wool.

4.      Name the animals who give us leather.

Ans: Goat, sheep and buffalo, give us leather.

5.      Name the animal that give us pearls.

Ans: Oyster gives us pearls.

6.      What is an oyster?

Ans: An oyster is a type of shell fish that has a rough shell with two parts, it is eaten both cooked and raw.

7.      Name some animals which are used as sea food.

Ans: Fish, prawns, lobsters and crabs, are used as sea food.

8.      Name some animals which are used as means of transport.

Ans: Horses, camels and elephants are used as means of transport.

9.      What are draught animals?

Ans: Draught animals are the animals which are used for pulling heavy loads.

10.  Name the animals which are used to draw wagons and carts.

Ans: Horses and oxen which are used to draw wagons and carts.

11.  Name five wild animals.

Ans: Monitor lizard, tiger, elephant, wild boar, giraffe are the wild animals.

12.  How are human beings destroying the natural surroundings of wild animals?

Ans: The human beings, are destroying the natural surroundings of wild animals by cutting down forests and by polluting rivers.

13.  Differentiate between extinct and endangered animals. Give two examples of each type.

Ans: i) Extinct animals are those animal species which are no longer living. Some examples are, Tasmanian tiger, quagga, passenger pigeon, golden toad and Caribbean monk seal etc.

ii) Endangered animals are those animal species that are in danger of becoming extinct. Animals, like African elephant, Bactrian camel, bald eagle, golden lion, tamarin and panda, are endangered animals.

14.  Name the wildlife sanctuary that is included in the list of the seven wonders of the natural world.

Ans: Kenya’s Masai Mara wildlife sanctuary.

15.  What is wildlife trade? Why is it harmful?

Ans: i) The illegal killing and poaching of animals for their body parts, is known as wildlife trade.

ii) Due to the wildlife trade, many species may disappear from earth.

16.  List the body parts of various animals which are being used for trading.

Ans: i) Elephants are hunted for their tusks. The tusks, or ivory, are used for making jewellery and decoration pieces.

ii) North and South American bears are also being killed for their gall bladders, which are then smuggled to other countries and used to make medicines.

iii) Rhinoceroses are being slaughtered for their horns. These, are grounded into powder form, to make medicines.

iv) Musk deer is becoming extinct because it is being hunted to obtain Kasturi, an ingredient of many perfumes.

v) A variety of mountain goat is hunted because its hair yield a very expensive variety of wool – pashmina.

vi) Tigers are killed for making use of their bones. The skins of tigers are used to decorate walls by hunters. Tiger claws and teeth are worn as jewellery by many superstitious persons who think that these can bring them good luck.

vii) Legs of frog are eaten as they are considered to be a ‘delicacy’.

viii) Caviar, another very costly delicacy, is made from the unfertilised eggs of a variety of fish. However, this has led to a steady decline in the number of this variety of fish.

17.  Why tigers are being killed by humans?

Ans:i) Tigers are killed for making use of their bones.

ii) The skins of tigers are used to decorate walls by hunters.

iii) Tiger claws and teeth are worn as jewellery by many superstitious persons who think that these can bring them good luck.

18.  Why elephants are being killed by humans?

Ans: Elephants are hunted for their tusks. The tusks, or ivory, are used for making jewellery and decoration pieces.

19.  Why Rhinoceroses are being killed by humans?

Ans: Rhinoceroses are being slaughtered for their horns. These, are grounded into powder form, to make medicines.

20.  Why Musk deers are being killed by humans?

Ans: Musk deer is becoming extinct because it is being hunted to obtain Kasturi, an ingredient of many perfumes.

21.  Why mountain goats are being killed by humans?

Ans: A variety of mountain goat is hunted because its hair yield a very expensive variety of wool – pashmina.

22.  Name the animals that can become man eaters.

Ans: Leopards and tigers can become man eaters.

23.  Which act has been passed by the Indian government to protect wildlife?

Ans: Government of India enacted the Wildlife Protection Act, 1972, to protect wildlife.

24.  What is the objective of Wildlife protection Act, 1972?

Ans: The objective of Wildlife Protection Act, 1972, is to control poaching and illegal trade in wildlife.

25.  Give the meaning of the term food chain.

Ans: Food chain is a process of ‘who eats whom’. A food chain shows how each living organism gets its food.

26.  Give one example of food chain in plains.

Ans: Leaves (eaten by), caterpillar (eaten by), a frog (eaten by), a snake (eaten by), an owl form one food chain.

27.  What is a foodweb?

Ans: The interconnection of a number of food chains, is called a foodweb.

28.  ______ shows how plants and animals are interconnected in many ways to help them survive in nature.

Ans: Food web

29.  Suggest the steps to prevent cruelty to animals.

Ans: i) Do not throw polythene bags in the garbage. Stray cattle can swallow them and they may die.

ii) Do not put birds in cages and fish in aquariums. They feel trapped in small spaces and their life span gets reduced.

iii) When visiting a forest, park or garden, one should not remove eggs of birds from their nests.

iv) Put some water in an earthen bowl and keep it outside, especially during summers.

v) If you have pets, give them the love and good care that they deserve. If the pet animal appears to be sick, take it to the veterinarian.

vi) Suggest your friends to treat animals with kindness and respect.

30.  Who is a veterinarian?

Ans: A doctor that looks after, heals and treats animals, is called a veterinarian.

31.  Name the largest animal rights group in the world.

Ans: PETA (People for the Ethical Treatment of Animals) is the largest animal rights group in the world.

32.  What is the slogan given by PETA?

Ans: PETA’s slogan is “animals are not for us to eat, wear, experiment on, or use for entertainment.”

33.  Name the four core issues that PETA focuses on.

Ans: PETA focuses on four core issues: factory farming, fur farming, animal testing, and animals in entertainment.