Why are some substances biodegradable and some non-biodegradable?

Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?

If all the waste we generate is biodegradable, will this have no impact on the environment?

What are the problems caused by the non-biodegradable wastes that we generate?

What is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?

Will the impact of removing all the organisms in a trophic level be different for different trophic levels? Can the organisms of any trophic level be removed without causing any damage to the ecosystem?

What will happen if we kill all the organisms in one trophic level?

Which of the following are environment-friendly practices? (a) Carrying cloth-bags to put purchases in while shopping (b) Switching off unnecessary lights and fans (c) Walking to school instead of getting your mother to drop you on her scooter (d) All of the above

Which of the following constitute a food-chain? (a) Grass, wheat and mango (b) Grass, goat and human (c) Goat, cow and elephant (d) Grass, fish and goat

Which of the following groups contain only biodegradable items? (a) Grass, flowers and leather (b) Grass, wood and plastic (c) Fruit-peels, cake and lime-juice (d) Cake, wood and grass

How can you help in reducing the problem of waste disposal? Give any two methods.

What is ozone and how does it affect any ecosystem?

Give any two ways in which non-biodegradable substances would affect the environment.

Give any two ways in which biodegradable substances would affect the environment.

What is the role of decomposers in the ecosystem?

What are trophic levels? Give an example of a food chain and state the different trophic levels in it.