Question:hard

Tropical forests play a key role as the world's carbon and wildlife reservoirs.

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Decide if the tense fits a general, permanent fact, and whether 'as' is the right preposition for the meaning intended.
Updated On: Jul 21, 2026
  • Play a key role as the world's
  • Had played a key role in the world's
  • Have been played a key role at the world's
  • Has played a key role for the world's
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The Correct Option is A

Solution and Explanation

Test the sentence by checking tense and preposition separately. The claim about forests being carbon and wildlife reservoirs is a permanent fact, which calls for the simple present, and the role described needs "as" rather than "in", "at", or "for".

  1. Play a key role as the world's: matches the plural noun "forests", stays in simple present for a general truth, and "as" correctly frames forests in the role of reservoirs.
  2. Had played a key role in the world's: past perfect wrongly implies the role is now over, and "in" does not carry the same "acting as" sense.
  3. Have been played a key role at the world's: turns an active role into a passive one, which does not make sense since forests actively provide this function.
  4. Has played a key role for the world's: the singular verb "has" does not agree with the plural "forests", breaking subject-verb agreement.

No change is needed, so the underlined part is correct as it stands, confirming option (a).

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