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science | Grade 7 | Notes | unit 4 | Environment

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Short Questions Unit # 4

1. What is meant by environment?
Answer: environment consists of all the things around an organism, which affect the life of that organism.
2. Which are the factors of the environment?
Answer: These are two types. 1. Biotic factors 2. A-biotic factors
3. Write the names of biotic factors of the environment.
Answer: Biotic means living things like animals, human beings, plants, and micro-organisms are called biotic factors.
4. Write the names of a- biotic factors of the environment.
Answer: A-biotic factors mean non-living things e.g. light, temperature, water, soil, and air.
5. What are consumers?
Answer: All animals cannot prepare food on their own. They depend on plants. They are called consumers.
6. What are producers?
Answer: All plants having green leaves can prepare food by the photosynthesis process. They are called producers.
7. What is meant by pollution?
Answer: Undesirable changes due to harmful materials are called pollution. There are four major types of pollution. 1. Water pollution. 2. Air pollution. 3. Land pollution. 4. Noise pollution.

8. What are the decomposers?

Answer: The organisms that decompose the dead bodies of animals and plants are called decomposers. These are bacteria and fungi. They change complex compounds into simple compounds or elements.
9. How many types of environments?
Answer: There are two types of environment. 1. Land environment. 2. Aquatic environment
The land environment is of three types. 1. Environment of plains. 2. Environment of the desert. 3. Environment of mountains.
10. Write down some important causes of water pollution.
Answer: Some important causes of water pollution are here as under
1. Untreated industrial water pollutes the water.
2. Chemical sprays for insecticide are washed away and carried into the rainwater.
3. Oil seeping out of tankers, is a major source of water pollution.
4. Sulphur dioxide, in the polluted air, gets dissolved in rainwater and comes down as acid rain.

11. What is meant by pollutants?

Answer: Materials causing pollution are called pollutants. Carbon dioxide, carbon monoxide, Sulphur dioxide, dust, and noise are pollutants.
12. How does air pollution affect human health?
Answer: The smoke is produced by burning fuel, traffic, and factories and entered the air. While breathing we take it into our body. It causes many diseases of the throat, lungs, skin, and eyes.
13. How does land pollution affect the life of organisms?
Answer: Harmful chemicals from land get their way into the plants and from there into animals and human bodies and may cause diseases.
14. What are the major sources of air pollution?
Answer: There are many causes of air pollution, like the burning of fuel and garbage in homes, factories and traffic produce smoke and poisonous gases. This smoke enters the atmosphere and pollutes the air. This may cause cancer, allergy, and diseases of the throat and lungs. It is the most harmful type of pollution.

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