STD-5, CHAPTER-7: IMPORTANCE OF WATER, EXTRA QUESTION ANSWERS

1.      State the uses of water.

Ans: i) We use water for drinking and other household activities like washing, bathing, cooking, cleaning and so on.

ii) Water is also used for irrigating the fields, generating electricity and for transportation.

2.      The human body contains _____percentage of water.

Ans: Human body contains about 70% water.

3.      Name any two water bodies that exist on the surface of earth.

Ans: Two water bodies that exist on the surface of earth are rivers, oceans and seas.

4.      How does water help in excretion of waste material from animal bodies?

Ans: i) The animal body produces waste materials.

ii) These waste materials get dissolved in water and are excreted in the form of urine.

5.      Describe the ways in which water is important for animals.

Ans: i) Water helps in the process of digestion of food.

ii) The nutrients present in food get dissolved in water. This helps their bodies to absorb nutrients.

iii) Water also help in excretion of waste material from animal bodies.

iv) Water is also a habitat for many animals.

6.       What are aquatic animals?

Ans: Animals living in water are called aquatic animals.

7.      Name some aquatic animals.

Ans: Fish, whale, seahorse, prawn and octopus are some aquatic animals.

8.      What are amphibious animals?

Ans: Animals that can live both in water and on land, are called amphibious animals.

9.      Name some amphibious animals.

Ans: Frog, Turtle and crocodile are some amphibious animals.

10.  List any four ways in which water is important for plants.

Ans: i) Water provides nutrients to plants in dissolved form.

ii) Water also helps in transporting nutrients to various parts of the plant.

iii) Plants require water for photosynthesis process.

iv) Plants require water for germination of seeds.

v) Water is also a habitat for many plants.

11.  What are aquatic plants?

Ans: Plants growing in water, are called as aquatic plants.

12.  Name some aquatic plants.

Ans: Water lily, lotus, water hyacinth, duckweed, water lettuce and hydrilla, are some aquatic plants.

13.  Kamal kakri is the ______ of the lotus plant.

Ans: Stem

14.  How do plants absorb water from the soil?

Ans: Plants absorb water from the soil with the help of their roots.

15.  What percentage of water is present in seas and oceans?

Ans: About 97% of water is present in seas and oceans.

16.  What percentage of water is present in rivers, lakes, ponds, streams and glaciers?

Ans: About 3% of water is present in rivers, lakes, ponds, streams and glaciers.

17.  What is ground water?

Ans: Water, present below the earth’s surface, is called as ground water.

18.  State the methods of drawing out ground water.

Ans: Ground water can be drawn out in many ways, like: i) From baolis or stepwells

ii) With the help of a water wheel or rehat.

iii) From a well using a pulley

iv) From tubewells.

19.  What is a stepwell?

Ans: i) A stepwell is a well having steps on all sides.

ii) This enables people to go down to fetch water.

20.  How can ground water be drawn out through tubewells?

Ans: i) In a tubewell, a long pipe is inserted deep into the ground where it dips below the ground water level.

ii) Water is then drawn up by using a hand pump or an electric pump.

21.  How is water supplied in cities?

Ans: i) There are well-planned water supply systems that supply water to homes and offices in the cities.

ii) In such systems, the river water is usually purified by a series of processes that make it fir for drinking.

iii) This purified water is then sent to homes and offices through a network of pumps and pipes.