Our Environment NCERT Questions


  1. Why are some substances biodegradable and some non-biodegradable?
  2. Give any two ways in which biodegradable substances would affect the environment.
  3. Give any two ways in which non-biodegradable substances would affect the environment.
  4. What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
  5. What is the role of decomposers in the ecosystem?
  6. What is ozone and how does it affect any ecosystem?
  7. How can you help in reducing the problem of waste disposal? Give any two methods.


  1. Which of the following groups contain only biodegradable items?
  2. Which of the following constitute a food-chain?
  3. Which of the following are environment-friendly practices?
  4. What will happen if we kill all the organisms in one trophic level?
  5. 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?
  6. What is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?
  7. What are the problems caused by the non-biodegradable wastes that we generate?
  8. If all the waste we generate is biodegradable, will this have no impact on the environment?
  9. Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?


  1. How does concentration of a pesticide change once it enters a food chain.
  2. In an ecosystem, rats feed on grains. Name the trophic level to which the rats belong.
  3. What will be the consequences if all the carbon of all fossil fuel is converted into carbon dioxide?
  4. If all the wastes we generate is biodegradable, what effect will this have on the environment? What value will be imbibed if people are made to understand that generation of waste should be restricted to be biodegradable only?
  5. In a colony, it was decided to remove a green park and construct an air conditioned shopping mall. Children of the colony took out a march against this decision with several placards to make the colony people aware of the importance of green plants.
    a. What are the ill effects of air conditioners?
    b. Design two placards which the children would have carried?
    c. Is the action taken by the children justified?
    d. How does the ecosystem get affected when plants are removed?
  6. In a food chain comprising frogs, insects, birds and grass, which one of the organisms is likely to have maximum concentration of harmful non-biodegradable chemicals in its body?
  7. It is often advised to stop our vehicles engine at red light and also to drive car / vehicles at constant speed.

Based on the above statement, answer the following question.

(i) Which type of fuel is used in vehicles? Is it renewable or nonrenewable.

(ii) How can you contribute towards saving these fuels at your level?

  1. Number of vultures is decreasing remarkably nowadays which is a matter of concern.
    (i) Vultures belong to which category of animal.

(ii) What is their role in nature to maintain ecological balance?

  1. Newspaper reports about the alarming increase in pesticides level in packed food items Some of states have even banned these food items.

(i) What are the sources of these pesticides in these food items?

(ii) Name the biological phenomenon associated with accumulation of pesticide in the food chain.

  1. 10.  Ozone depletion / Ozone hole is a cause of concern now a days.

(i) What are the causes of ozone depletion?

(ii) As students what steps will you advise to reduce ozone depletion?

  1. 1   Acid rain is causing damage to monuments / Buildings etc. and also harm the flora and fauna.

(i) What is the cause of acid rain?

(ii) What essential changes in our daily life can lie done to prevent acid rain / damage caused by acid rain.

  1. Plastic production is increasing day by day in spite of the fact that plastic is harmful for the environment. Based on the above statement answer the following.

(i) What are the harmful effects of plastic usage?

(ii) In our day to day situation what are the alternatives that we can use instead of plastics.

  1. With the help of an example show that ‘reuse’ strategy is better than ‘recycling’.
  2. Construct an aquatic food chain showing four trophic levels.
  3. To protect the food plants from insects, an insecticide was sprayed in small amounts but it was detected in high concentration in human beings. How did it happen?
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