DAV Class 4 Science Solution Chapter 10 Water Pollution
DAV School Books Class 4 Science Solution Chapter 10 Water Pollution all Question Answer. DAV Class 4 10th Chapter Water Pollution full Chapter explanation by expert teacher.
DAV School Books Class 4 Science Solution Chapter 10 Water Pollution:
A.)
1.) Rain water, when just formed
2.) Polluted
3.) Pesticides
4.) Polluted
5.) Industrial
B.)
1.) False
2.) True
3.) True
4.) False
5.) False
C.)
1.) c(cholera)
2.) c(it reduce fertility of soil)
3.) d(cut off the supply of oxygen for aquatic animals)
4.) d(people do not wash cloths or bathe their cattle in river)
D.)
1.) Dust and smoke particles ,these two materials can make rain water impure.
2.) Two human activities which can cause water pollutions are,
- People wash their clothes and bathe in river water. Some people bathe their cattle in river.
- People throw domestic waste in rivers.
- Waste materials and harmful chemicals from factories are often dumped in the river.
- Thypoid and jaundice these two diseases may be caused by drinking polluted water.
- Farmers use chemical fertilizers and pesticides to increase the production of their crops.
E.
1.) Industrial and agricultural wastes increase the growth of micro-organisms in water. This can reduce the supply of oxygen for the aquatic animals. Aquatic animals get infected by polluted water. When other animals eat these infected animals they also become sick.
2.) When polluted water use for irrigation the fertility of soil gets reduced and crops get damaged.
3.) Oil spills from cover on the surface of water. Oil spilled by tankers and oil wells pollutes sea water. This cut off the supply of oxygen to the animals living under water.
4.) Water pollution has many harmful effects. Some of harmful effects of water pollution,
- Poisonous chemical from factories kill marine animals.
- Industrial and agriculture wastes increase the growth of micro-organisms in water. This can reduce the supply of oxygen for the aquatic animals.
- Oil spills from a cover on the surface of water. This cut of the supply of oxygen to the animals living under water.
- When polluted water is used for irrigation the fertility of soil gets reduced and crops can get damaged.
5.) Some ways of reducing water pollution are given below:-
- Waste from factories and power houses should not be allowed to flow into rivers directly.
- Water from drains or sewage should not be allowed to enter into wells or rivers.
- People should not wash their clothes or use soaps if they bathe in rivers.
- The use of chemicals fertilizers should be minimized. Instead natural manure should be used.
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