Chapter 13 Our Environment Questions-02
Questions
1. Why are some substances biodegradable and some non-biodegradable?
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Answer
Some substances such as metal, glass, plastic, etc. which cannot be decomposed by the living organisms are non-biodegradable wastes. These substances are non-biodegradable because the micro-organisms do not have enzymes that can digest these substances. Therefore, we classify them as non-biodegradable wastes. Other substances such as paper, vegetable wastes, etc. that can be easily broken down by enzymes are biodegradable wastes.
2. Give any two ways in which biodegradable substances would affect the environment.
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Answer
Biodegradable substances affect the environment in the following ways:
(i) The biodegradable substances such as tree leaves, plant parts, and kitchen wastes can be used as humus after composting. This will enhance the soil fertility.
(ii) The biodegradable substances mainly contain carbon. These substances after decomposition release that carbon back into the atmosphere.
3. Give any two ways in which non-biodegradable substances would affect the environment.
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Answer
Non-biodegradable substances affect the environment in the following ways:
(i) They contaminate soil and water resources as they cannot be decomposed by micro-organisms.
(ii) These substances, when accidentally eaten by stray animals, can harm them and can even cause their death.
