STD-4, CHAPTER-8: WATER SCARCITY AND CONSERVATION OF WATER, EXERCISE Q/As

 

A.     FILL IN THE BLANKS.

1.      The earth is known as a ______ planet.

Ans: Blue

2.      ______ and ______ are two major natural sources of water.

Ans: Rain and Snow

3.      Setting-up of factories cause a ______ in the level of underground water.

Ans: decrease

4.      Cutting of trees in the forests causes a ______ in rainfall.

Ans: decrease

5.      Use of water sprinkler for irrigation reduces the _____ of water.

Ans: wastage

B.      MATCH THE FOLLOWING:

1.      Cutting of trees in the forests                             (a) water conservation

2.      Collecting rain water for                                    (b) dam

day-to-day use                        

3.      Proper utilisation of water                                  (c) deforestation

and avoiding its wastage                                        

4.      A method of preserving large                             (d) rain water harvesting

quantity of water and checking

floods                             

      Ans:

1.      Cutting of trees in the forests                             (c) deforestation

2.      Collecting rain water for                                    (d) rain water harvesting

day-to-day use                        

3.      Proper utilisation of water                                  (a) water conservation

and avoiding its wastage                                        

4.      A method of preserving large                             (b) dam

quantity of water and checking

floods                             

 

C.      TICK THE CORRECT OPTION.

1.      Two major natural sources of water are –

(a)   Rain and wells                                      

(b)   Snow and rivers

(c)    Rain and snow                 

(d)   Ground water and rivers

Ans: Rain and snow

2.      Planting of more trees will help in –

(a)   Reducing the ground water level                                      

(b)   Setting-up more factories

(c)    deforestation                

(d)   increasing the rainfall

      Ans: increasing the rainfall

3.      We can avoid wastage of water by –

(a)   Using water sprinkler                                      

(b)   Over-irrigation

(c)    Washing our car with a jet of water                 

(d)   Allowing water to leak from taps

      Ans: Using water sprinkler

D.     ANSWER THE FOLLOWING QUESTIONS IN BRIEF.

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.      Name three sources of fresh water.

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

3.      State the effect of deforestation on rainfall.

Ans: Deforestation results in a decrease in rainfall.

4.      State two reasons that are leading to cleaning 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.

5.      State one utility of dams.

Ans: Dams preserve a large quantity of water.

E.      ANSWER THE FOLLOWING QUESTIONS.

1.      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.

2.      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.

3.      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.

4.      How should the fields be irrigated to reduce 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.

5.      State any three 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) Use a mug and bucket to take bath instead of a shower.

iii) Get the leaking pipes and taps repaired immediately.

STD - 4, CHAPTER - 4 : PLANTS AROUND US, EXERCISE QUESTIONS AND ANSWERS

 

A.     FILL IN THE BLANKS.

1.      Plants, growing on hills, are tall, straight and have a _____ shape.

Ans: Conical

2.      ______ and ______ are two of the trees that grow on plains.

Ans: Mango, Banyan

3.      Breathing roots are also called ______ roots.

Ans: aerial roots

4.      ______ is an underwater plant.

Ans: Hydrilla

5.      Lotus stem is eaten as a _______.

Ans: vegetable

B.      MATCH THE FOLLOWING:

1.      Evergreen trees                             (a) rice

2.      Needle-like leaves                        (b) cactus

3.      No leaves                                        (c) mangrove

4.      Breathing roots                             (d) aquatic plant

5.      Air filled cavities                           (e) rubber and teak

6.      A cultivated crop                           (f) pine and cedar

      Ans:

1.      Evergreen trees                             (e) rubber and teak

2.      Needle-like leaves                        (f) pine and cedar

3.      No leaves                                        (b) Cactus

4.      Breathing roots                             (c) mangrove

5.      Air filled cavities                            (d) aquatic plant

6.      A cultivated crop                           (a) rice

 

C.      TICK THE CORRECT OPTION.

1.      It is a free floating plant -

(a)   Water hyacinth        (b) hydrilla          (c) coconut        (d) lotus

      Ans: Water hyacinth

2.      These are unwanted plants -

(a)   Cactus        (b) Grass          (c) Mangroves        (d) Weeds

      Ans: Weeds

3.      It can survive in soil with very little water -

(a)   Banyan        (b) Teak          (c) Rubber        (d) Cactus

      Ans: Cactus

D.     ANSWER THE FOLLOWING QUESTIONS IN BRIEF.

1.      What are terrestrial plants?

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

2.      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.

3.      Name two trees growing in hot and wet regions.

Ans: Two trees growing in hot and wet regions are - Teak, rubber, coconut, pepper, cotton, rice and banana. (any two)

4.      Name an underwater plant. What kind of leaves does it have?

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

5.      What is ploughing? 

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

E.      ANSWER THE FOLLOWING QUESTIONS.

1.      List the different habitats of terrestrial plants.

Ans: The different habitats of terrestrial plants are,

i) Hills

ii) Plains

iii) Hot and Wet regions

iv) Marshy areas

v) Desert areas

2.      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.

3.      What are aquatic plants? State their types and give two examples of each type.

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

ii) Aquatic plants are of two types:

a)      Floating Aquatic Plants

- Free floating plants (Two examples are: Water lettuce and Water hyacinth)

- Fixed Aquatic Plants (Two examples are: Lotus and Water lily)

b)     Underwater Plants (Two examples are: Hydrilla and Kelps)

 

4.      What are cultivated plants?

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

ii) The cultivated plants grow and give us the desired products.

iii) Examples: Sugarcane, maize, wheat and rice.

5.      Why should weeds be removed from the fields?

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

iii) They can harm the growth of cultivated plants.

ii) Weeds are removed so that they do not consume water and fertilisers meant for the main crop

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