| Assertion (A): | Removal of a keystone species from a community affects community structure significantly. | 
| Reason (R): | Keystone species are always the apex predators in an ecosystem. | 
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). | 
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). | 
| 3. | (A) is True but (R) is False. | 
| 4. | Both (A) and (R) are False. | 
| Assertion (A): | The ‘Sixth Extinction’ presently in progress is different from the previous episodes of species extinction. | 
| Reason (R): | The current species extinction rates are estimated to be 100 to 1,000 times faster than in the pre-human times | 
| 1. | Both (A) and (R) are True and (R) correctly explains (A). | 
| 2. | Both (A) and (R) are True but (R) does not correctly explain (A). | 
| 3. | (A) is False but (R) is True. | 
| 4. | (A) is True but (R) is False. | 
Consider the given two statements:
| Statement I: | The broadly utilitarian argument for conserving biodiversity says that humans derive countless direct economic benefits from nature. | 
| Statement II: | The ethical argument for conserving biodiversity says that biodiversity plays a major role in many ecosystem services that nature provides. | 
| 1. | Statement I is correct; Statement II is incorrect | 
| 2. | Statement I is incorrect; Statement II is incorrect | 
| 3. | Statement I is incorrect; Statement II is correct | 
| 4. | Statement I is correct; Statement II is correct | 
| Statement I: | More than 25% of the drugs currently sold in the market worldwide are derived from plants. | 
| Statement II: | Amazon forest is estimated to produce, through photosynthesis 5 % of the total oxygen in the earth’s atmosphere. | 
| 1. | Statement I is incorrect; Statement II is incorrect | 
| 2. | Statement I is incorrect; Statement II is correct | 
| 3. | Statement I is correct; Statement II is incorrect | 
| 4. | Statement I is correct; Statement II is correct | 
| 1. | The number of lichens is much more than the number of algae | 
| 2. | The number of mosses is much less than the number of ferns and allies | 
| 3. | The number of angiosperms is equal to the number of gymnosperms | 
| 4. | The number of fungi is much more than the number of algae, ferns and allies, mosses and lichens put together | 
A stable community in an ecosystem:
| I: | should show a considerable increase in productivity every year | 
| II: | must be either resistant or resilient to occasional man-made and natural disturbances | 
| III: | must be resistant to invasions by alien species | 
1. Only I and II are correct
2. Only I and III are correct
3. Only II and III are correct
4. I, II and III are correct
| 1. | Montreal, 1987 | 2. | Kyoto, 1997 | 
| 3. | Rio de Janeiro, 1992 | 4. | Johannesburg, 2002 | 
| 1. | 2002 | 2. | 1985 | 
| 3. | 1992 | 4. | 1986 |