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.

STD 4, CHAPTER 4: PLANTS AROUND US, EXTRA QUESTION AND ANSWERS

1.      Define habitat.

Ans: The place, where a living thing lives most comfortably, is called its habitat. The habitat is thus, the natural home of a living thing.

2.      Define terrestrial plants.

Ans: Plants which grow on land, are called terrestrial plants.

3.      List the different habitats of terrestrial plants.

Ans: The different habitats of terrestrial plants are, Hills, plains, hot and wet regions, marshy areas, desert areas, etc.

4.      Name some plants which grow on the hills.

Ans: Pine, deodar, cedar, spruce and fir, grow on the hills.

5.      What is the shape of the plants of the hills?

Ans: Plants of the hills, generally have a conical shape.

6.      What is the shape of the leaves of the plants of hills?

Ans: The leaves of the plants of hills are narrow and needle shaped.

7.      How does the conical shape help the plants of hills?

Ans: The conical shape of these trees does not allow snow to get deposited on them.

8.      Name some plants that grow in plains.

Ans: Peepal, banyan, mango, sal, sheesham, grow in plains.

9.      Name the plants growing in hot and wet regions.

Ans: Teak, rubber, coconut, pepper, cotton, rice and banana grow in hot and wet regions.

10.  Why are the trees, of hot and wet regions called ‘evergreen trees’?

Ans: i) The trees of hot and wet regions generally have a large number of leaves.

ii) They shed their leaves gradually.

So, they are called evergreen trees.

11.   Define a marshy area.

Ans: Marshy area means a very wet, muddy area on land.

12.  Name the plants growing in marshy areas.

Ans: Mangroves grow in marshy areas.

13.  Why do roots of mangroves come out of the soil?

Ans: Roots of mangroves come out of the soil, to get oxygen.

14.  What are ‘breathing roots’ or ‘aerial roots’?

Ans: The roots that come out of the soil, above the water level, and take oxygen from air, are called breathing roots or aerial roots.

15.  Name the plants having aerial roots.

Ans: Banyan, maize and mangroves, have aerial roots.

16.   How is cactus plant able to grow in desert conditions?

Ans: i) It can survive in soil that has very little water.

ii) It has a green stem and well developed roots. The stem stores water.

iii) Cactus plant has spines instead of leaves.

17.  What is the meaning of the term, ‘Aquatic’?

Ans: Aqua means ‘water’ and aquatic means ‘existing or happening in water’.

18.  Define aquatic plants.

Ans: Plants, found in water, are called aquatic plants.

19.   What are the two types of aquatic plants?

Ans: The two types of aquatic plants are, i) Floating Aquatic plants

                                                                          ii) Underwater plants

20.  What are the two types of Floating aquatic plants?

Ans: The two types of Floating aquatic plants are, i) Free Floating Plants

                                                                                         ii) Fixed Aquatic plants

21.  Name some Free floating aquatic plants.

Ans: Water lettuce, water hyacinth and duckweed are the free floating aquatic plants.

22.  Why some plants float on the surface of water?

Ans:i) Some plants are not attached to any surface.

ii) They have air filled cavities in their leaves and stems.

iii) These cavities make them light and help them to easily float on water.

23.  Name some fixed aquatic plants.

Ans: Lotus and water lily are the fixed aquatic plants.

24.  What type of leaves do the fixed aquatic plants have?

Ans: The fixed aquatic plants have broad leaves.

25.  Name the stem which is eaten as a vegetable.

Ans: The stem of lotus (kamal kakri), is eaten as a vegetable.

26.  Name an underground plant. What kind of leaves does it have?

Ans: Hydrilla is an underground plant. It has pointed and strap-like leaves.

27.  How does the Hydrilla plant help the aquatic animals?

Ans:i) Hydrilla increase the oxygen content of water and remove carbon dioxide from it.

ii) This helps in making water suitable for fish and other aquatic animals and helps them to get enough oxygen.

28.  What are cultivated plants?

Ans: Those plants which are grown in the fields by the farmers, are called as cultivated plants.

29.  What is ploughing?

Ans: The process of digging the soil or loosening the soil, is called ploughing.

30.  How ploughing is done?

Ans: Ploughing is done with the help of a plough or a tractor.

31.  An iron structure used in the process of ploughing, is called a _________.

Ans: Plough

32.  What are weeds?

Ans: The undesirable plants in the field are called as weeds.

33.  Why should weeds be removed from the fields?

Ans: Weeds are removed so that they do not consume water and fertilisers meant for the main crop.

STD 3,CHAPTER 4: IMPORTANCE OF PLANTS, EXTRA QUESTIONS AND ANSWERS

 

1.      In which forms, do we get food from plants?

Ans: We get food from plants in the form of fruits, vegetables, pulses and grains.

2.      Name some useful products that we get from plants?

Ans: We get wood, paper, rubber, cotton, oils and spices from plants.

3.      Name some plants which are used to make medicines.

Ans: Tulsi, Neem, Ginger and garlic are used to make medicines.

4.      How plants are useful for us?

Ans: i) Plants provide us food in the form of fruits, vegetables, pulses and grains.

ii) Plants give us wood, paper, rubber, cotton, oils and spices.

iii) Some plants like tulsi, neem, ginger and garlic, are used to make medicines.

iv) Plants give us oxygen.

v) Plants also help in soil conservation.

5.   Which gas is required for breathing?

Ans: Oxygen gas is required for breathing.

6.      What do you mean by a purifier?

Ans: Something which helps in removing impurities, is called as a purifier.

7.      How do plants act as air purifiers?

Ans: Plants give out oxygen gas during the day. This helps to increase the amount of oxygen in the air and, thereby, purifies it. Hence, plants act as air purifiers.

8.      How do plants help the soil?

Ans: Plants bind the soil with the help of their roots. So, plants help in soil conservation.

9.      What is deforestation? Is it good or bad for all of us?

Ans: Cutting down of trees is called as deforestation. It is bad for all of us.

10.  Write any two ill-effects of deforestation.

Ans: i) Due to deforestation, animals are not getting shelter.

ii) Quantity of oxygen is also decreasing in the atmosphere.

11.  What is afforestation?

Ans: Planting new trees is called afforestation.

12.  Mention any two benefits of afforestation.

Ans: i) Due to afforestation, animals will get their shelter.

ii) We will get purified air.

13.  Suggest some ways that can help to conserve plants.

Ans: i) We should only use those branches and leaves that have fallen down.

ii) We should put a ban on deforestation.

iii) We should promote afforestation.

iv) We should take full care of the saplings.

v) We should take steps to protect forests against forest fires. 

14. Suggest how one can take care of the saplings planted by him/her?

Ans: i) We should water the saplings regularly.

ii) We can use compost for the better growth of the saplings.

iii) We should protect the saplings from insects and other animals who can harm it.

15. Name the oldest living tree.

Ans: Tjikko is the oldest living tree. (It is 9,550 years old)