Multiple choice

Some bat caves, like honeybee hives, have residents that take on different duties such as defending the entrance, acting as sentinels and to sound a warning at the approach of danger, and scouting outside the cave for new food and roosting sites.

  1. acting as sentinels and to sound

  2. acting as sentinels and sounding

  3. to act as sentinels and sound

  4. to act as sentinels and to sound

  5. to act as sentinels and sound to
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

(B), The whole sentence is following a continuous formation, that is 'ing' is added after each verb. Hence the incorrect portion should also follow the same, so (B) is correct.

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