DAV class 4 Science Chapter 10 Solutions

DAV Class 4 Science Chapter 10 Water Pollution Solutions contain enough material to allow students to establish a solid foundation with the fundamentals of the DAV Class 4 Science Textbook. DAV Class 4 science students who practice Dav Class 4 Science Solutions Question Answer on a regular basis are more likely to do well in their school exams.

DAV CLASS 4 Science Chapter 10 Water Pollution Question and Answer

A. Fill in the blanks.

1. Rain Water is the purest form of water.

2. Water containing impurities is called polluted water.

3. Chemical fertilisers and pesticides used by farmers, can cause water pollution.

4. Drinking polluted water can cause diseases like diarrhea and jaundice.

5. Industrial and agricultural wastes increase the growth of micro-organisms in water.

B. Write True and False for the following statements.

1.River water is the purest form of water.False
2. Polluted water may contain dust, germs and smoke.True
3. Throwing domestic waste, in rivers, causes water pollutionTrue
4. Increased growth of micro-organisms in water increases the amount of oxygen for aquatic animals.False
5. Use of chemical fertilisers helps in preventing water pollution.False

C. Tick (✅) the correct option.

1. A disease that may be caused by drinking polluted water is—
(a) malaria
(b) cough
(c) cholera
(d) dengue

2. Polluted water should not be used for irrigation because—
(a) it can harm aquatic animals
(b) it pollutes river water
(c) it reduces fertility of soil
(d) it increases the production of crops

3.Oil spills in the sea are harmful because they—
(a) decrease the level of water in sea
(b) infect the aquatic plants
(c) increase the growth of micro-organisms in water
(d) cut off the supply of oxygen for aquatic animals

4. Pollution of river water can be reduced if—
(a) chemical fertilisers are used for increasing production of crops
(b) farmers use sprinklers for irrigating their fields
(c) water is allowed to stagnate around the river banks
(d) people do not wash clothes or bathe their cattle in rivers

D. Answer the following questions in brief.

1. Name any two materials which can make rain water impure.

Ans: Harmful gases and dust particles

2. Name any two human activities which can cause water pollution.

Ans: a) People wash clothes and bathe in river.
b) Throwing domestic waste in river.

3. Which two pollutants are often dumped by the factories into the rivers?

Ans: Waste materials and harmful chemicals.

4. Name any two diseases that may be caused by drinking polluted water.

Ans: Typhoid and Diarrhea

5. Write the names of two types of materials, used by farmers, to increase the production of crops.

Ans: Chemical fertilizers and pesticides

E. Answer the following questions.

1. How do wastes, from factories and fields, affect aquatic animals?

Ans: Waste from factories increase the growth of microorganism in water. This reduces the supply of oxygen for aquatic animals.

2. How can polluted water affect the crops?

Ans: When polluted water is used for irrigation, the fertility of soil gets reduced and cropes can get damged.

3. Why are oil spills harmful for marine life?

Ans: Oil spills form a cover on the surface of the water. This cuts off the supply of oxygen to animals living under water.

4. State any four effects of water pollution.

Ans: a) Poisonous chemicals from factories kill marine animals.
b) Drinking polluted water cause disease like diarrhea, cholera, jaundice.
c) Polluted water reduces the fertility of the soil.
d) Aquatic plants get infected by polluted water.

5. State four ways of reducing water pollution.

Ans: a) Wastes from factories should not be allowed to flow into rivers directly.

b) People should not wash clothes in rivers.

c) Water from drains or sewage should not be allowed to enter into wells or rivers.

d) Use of chemical fertilizers should be minimised.

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