To withstand extreme environmental conditions, microscopic creatures called tardigrades ______ a reversible state of suspended animation known as cryptobiosis. In this state, their metabolism drops to nearly zero, allowing them to survive without water for decades.

4
reading

Which choice completes the text so that it conforms to the conventions of Standard English?

A

enter

B

to enter

C

having entered

D

entering

Correct Answer: A

Choice A is the best answer. The subject "tardigrades" is plural. The verb must agree with the subject and fit the context of a general scientific fact. "Enter" is the correct plural, simple present tense verb.