Directions (26-30): In each of the question given below, a statement has been given with a blank. Some words or phrases have been given in the options following the statement. Choose the most appropriate word or phrase that could fit in the statement to make it contextually meaningful and grammatically correct.

Biosphere reserves are ___________ for the future of our planet.

The correct answer is vital.

Step-by-step Explanation:

1. Analyze the context of the sentence:
The sentence discusses "Biosphere reserves" and their relationship to "the future of our planet." Biosphere reserves are protected areas meant for the conservation of plants and animals. This indicates a positive and important contribution to the planet's future.

2. Evaluate the given options:
- tired: This means exhausted or weary. It does not fit contextually as biosphere reserves cannot be "tired" for the future of our planet.
- inactive: This means not engaging in activity or passive. This has a neutral or negative connotation and does not fit the constructive role of biosphere reserves.
- unique: This means being the only one of its kind; unlike anything else. While biosphere reserves can be unique, saying they are "unique for the future" is grammatically and contextually less fitting than describing their importance.
- vital: This means absolutely necessary, essential, or important. This fits perfectly, highlighting that biosphere reserves are crucial or essential for the future of our planet.
- inert: This means lacking the ability or strength to move, or chemically inactive. It is contextually inappropriate.

3. Conclusion:
The word vital is the most grammatically correct and contextually meaningful word to fill the blank.