Assertion (A) : The amount of ozone in the atmosphere began to drop sharply in the 1980s.

Reason (R) : The oxygen atoms combine with molecular oxygen to form ozone.

options

1. (A) and (R) are true and (R) is the reason for (A).
2. (A) and (R) are true and (R) is not the reason for (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.

(A) and (R) are true and (R) is not the reason for (A).

Reason —

• Assertion (A) is true because scientific studies in the 1980s showed a significant depletion of the ozone layer, particularly over Antarctica due to the release of chlorofluorocarbons (CFCs) and other pollutants, which break down ozone molecules in the stratosphere, leading to the formation of the ozone hole.

• Reason (R) is true because it describes how ozone is naturally formed in the atmosphere (O + O₂ → O₃). However, it does not explain why the ozone amount dropped in the 1980s. The drop was due to ozone destruction by CFCs, not its natural formation process.

Hence, (A) and (R) are true and (R) is not the reason for (A).