Unit 4
1 Define environment.
Ans All living and non living things surrounding an organism are collectively called its environment.
2 A few thousand years ago how people obtained their food?
Ans People obtained their food by gathering fruits, vegetables, leaves, roots of different plants or by hunting animals.
3 What steps have been taken by human to fulfill the needs of increased population?
Ans They develop agriculture. they made industries. they invented different means of transportation.
4 Define pollution.
Ans The addition of unwanted and harmful materials n the environment is called pollution.
5 Why do humans cut forests?
Ans Humans cut forest to get more food, more place, wood, paper etc.
6 What is the effect of cutting of forest?
Ans Cutting of forest affects the climate.the habitats of of wild animals and plants are also damaged.
7 What is the effect of using fuel in industries, transportation and in agriculture?
Ans It releases harmful gases in air.
8 How many trees are cut to make paper of Sunday newspapers in America?
ANS 500,000 trees are cut to make paper of Sunday newspapers in America.
9 Define habitat.
Ans The place where an organism lives is called its habitat.
10 Define population.
Ans All the organism of same type that live in the same area at a particular time.
11 Define climate.
Ans The weather conditions in an area in general ,e.g. temperature, humidity, wind, rain etc
12 How many kinds of pollution are there?
Ans There are three kinds of pollution i.e. air pollution, water pollution and land pollution.
13 Which gas is produced when fuel is burned in industries?
Ans Carbon dioxide is produced when fuel is burned in industries.
14 Name some diseases caused by air pollution.
Ans Smoke in air causes diseases of lungs, skin and eyes.
15 What is global warming?
Ans Due to air pollution, our earth is becoming hotter day by day. It is called global warming.
16 what type of water is there when rivers and streams begin from mountains?
Ans when rivers and streams begin from mountains their water is clean and pure.
17 Which things are mixed when water canals pass through the agricultural areas?
Ans when water canals pass through the agricultural areas fertilizers and pesticides mixed with water.
18 Name diseases which are caused by bacteria which are present in polluted water?
Ans Cholera , typhoid, diarrhea and dysentery.
19 Why sewage water produces bad smell?
Ans Sewage water produces bad smell due to two gases i.e. ammonia and hydrogen sulphide.
20 How many people die each year after consuming polluted water?
Ans In Asia, 5 to 10 million people die each year after consuming polluted water.
21 Write any two reason of land pollution.
Ans We dump home and factory wastes in soil. Plastic bags are not properly disposed of and are thrown here and there.
22 How much energy is saved by recycling one aluminum can?
Ans The energy saved by recycling one aluminum can is enough to operate a tv set for 3 hours.
23 Write down any two measure to reduce pollution.
Ans Forest should not be cut down and new trees should be planted. Such methods should be used by which the dangerous gases are removed from smoke of factories and vehicles.
24 What is meant by biodegradable material?
Ans The materials which can be broken down into simpler compounds by microorganism are called biodegradable materials.
25 What is ment by non-biodegradable materials?
Ans The materials which cannot be broken down into simpler compounds by microorganism are called biodegradable materials.
26 What is the effect of chemicals used in insect-killer sprays?
Ans The chemicals used in insect-killer sprays are non-biodegradable. Such chemicals are harmful and cause dangerous diseases.
27 How much time is taken by banana peel, paper, milk pack and aluminum soda can to break down into biodegradable materials?
Ans Banana peel takes about two months, paper takes three months, milk pack takes five years and aluminum soda can takes 350 years.
28 By which process we can prepare useful material s from garbage?
Ans Recycling is a process by which process we can prepare useful material s from garbage.
29 Why we re-cycle the non-biodegradable wastes?
Ans We re-cycle the non-biodegradable wastes to make new things from them.
30 Why traffic smoke is harmful to your environment?
Ans Because it pollutes the air and cause global warming.
31 Plants are useful to protect our environment .justify this statement.
Ans Plants absorb carbon dioxide and release oxygen in the environment.
32 How water canal is polluted when it passes through agricultural land?
Ans When water canal passes through agricultural lands, fertilizers and pesticides get mixed into the water.
33 Write kinds of pollution caused by industries.
Ans Industries cause all the types of pollution. they produce toxic waste materials which go to air, water and land.
1 Define environment.
Ans All living and non living things surrounding an organism are collectively called its environment.
2 A few thousand years ago how people obtained their food?
Ans People obtained their food by gathering fruits, vegetables, leaves, roots of different plants or by hunting animals.
3 What steps have been taken by human to fulfill the needs of increased population?
Ans They develop agriculture. they made industries. they invented different means of transportation.
4 Define pollution.
Ans The addition of unwanted and harmful materials n the environment is called pollution.
5 Why do humans cut forests?
Ans Humans cut forest to get more food, more place, wood, paper etc.
6 What is the effect of cutting of forest?
Ans Cutting of forest affects the climate.the habitats of of wild animals and plants are also damaged.
7 What is the effect of using fuel in industries, transportation and in agriculture?
Ans It releases harmful gases in air.
8 How many trees are cut to make paper of Sunday newspapers in America?
ANS 500,000 trees are cut to make paper of Sunday newspapers in America.
9 Define habitat.
Ans The place where an organism lives is called its habitat.
10 Define population.
Ans All the organism of same type that live in the same area at a particular time.
11 Define climate.
Ans The weather conditions in an area in general ,e.g. temperature, humidity, wind, rain etc
12 How many kinds of pollution are there?
Ans There are three kinds of pollution i.e. air pollution, water pollution and land pollution.
13 Which gas is produced when fuel is burned in industries?
Ans Carbon dioxide is produced when fuel is burned in industries.
14 Name some diseases caused by air pollution.
Ans Smoke in air causes diseases of lungs, skin and eyes.
15 What is global warming?
Ans Due to air pollution, our earth is becoming hotter day by day. It is called global warming.
16 what type of water is there when rivers and streams begin from mountains?
Ans when rivers and streams begin from mountains their water is clean and pure.
17 Which things are mixed when water canals pass through the agricultural areas?
Ans when water canals pass through the agricultural areas fertilizers and pesticides mixed with water.
18 Name diseases which are caused by bacteria which are present in polluted water?
Ans Cholera , typhoid, diarrhea and dysentery.
19 Why sewage water produces bad smell?
Ans Sewage water produces bad smell due to two gases i.e. ammonia and hydrogen sulphide.
20 How many people die each year after consuming polluted water?
Ans In Asia, 5 to 10 million people die each year after consuming polluted water.
21 Write any two reason of land pollution.
Ans We dump home and factory wastes in soil. Plastic bags are not properly disposed of and are thrown here and there.
22 How much energy is saved by recycling one aluminum can?
Ans The energy saved by recycling one aluminum can is enough to operate a tv set for 3 hours.
23 Write down any two measure to reduce pollution.
Ans Forest should not be cut down and new trees should be planted. Such methods should be used by which the dangerous gases are removed from smoke of factories and vehicles.
24 What is meant by biodegradable material?
Ans The materials which can be broken down into simpler compounds by microorganism are called biodegradable materials.
25 What is ment by non-biodegradable materials?
Ans The materials which cannot be broken down into simpler compounds by microorganism are called biodegradable materials.
26 What is the effect of chemicals used in insect-killer sprays?
Ans The chemicals used in insect-killer sprays are non-biodegradable. Such chemicals are harmful and cause dangerous diseases.
27 How much time is taken by banana peel, paper, milk pack and aluminum soda can to break down into biodegradable materials?
Ans Banana peel takes about two months, paper takes three months, milk pack takes five years and aluminum soda can takes 350 years.
28 By which process we can prepare useful material s from garbage?
Ans Recycling is a process by which process we can prepare useful material s from garbage.
29 Why we re-cycle the non-biodegradable wastes?
Ans We re-cycle the non-biodegradable wastes to make new things from them.
30 Why traffic smoke is harmful to your environment?
Ans Because it pollutes the air and cause global warming.
31 Plants are useful to protect our environment .justify this statement.
Ans Plants absorb carbon dioxide and release oxygen in the environment.
32 How water canal is polluted when it passes through agricultural land?
Ans When water canal passes through agricultural lands, fertilizers and pesticides get mixed into the water.
33 Write kinds of pollution caused by industries.
Ans Industries cause all the types of pollution. they produce toxic waste materials which go to air, water and land.
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