An agreement question with forms of one verb tests whether the verb matches its subject, who or what the sentence is about. First, sort the verb forms by number: singular forms go with it, and plural forms go with they. Then find the true subject, crossing out opening phrases and descriptions. One thing takes a singular verb, and more than one takes a plural verb. Match that number rather than the nearest noun, which may belong to a phrase.
Hints
- Hint 1
Ask what the sentence describes as too limited. That tells you which part of the sentence must match the verb.
- Hint 2
The phrase before the first comma gives background. Set it aside so you can read the main part of the sentence.
- Hint 3
Try removing the phrase that starts with of. Replace the remaining subject with it or they and test the verb forms with that pronoun.
Step-by-step
Find what is too limited
Step 1Sort the verb forms
Compare the choices by trying each verb form with it or they. The forms remain, have remained, and are remaining all go with they, so they're plural even though their tenses differ. In the longer forms, the helpers have and are are the parts that show the number. The sentence needs a verb before too limited, so number comes first: we need to know which thing is being described as limited.
- Step 2
Read past the descriptions
Despite years of study gives background, so we can set that opening phrase aside. What in the rest of the sentence is described as limited? The phrase of data collected from deep-sea hydrothermal vents tells us what the array contains and where the data came from; it doesn't make the data or vents the subject of the blank's verb. Reading past that whole phrase leaves array as the true subject, with the blank saying that the array is too limited. The plural noun vents sits closest to the blank, but it's inside the description of the data rather than the part that tells us what is limited.
- Step 3
Match the singular subject
How many things does the array name? It names one group, even though the group contains data from many vents, so the array takes a singular verb. Replace the subject with it to check: it remains too limited works, and remains is the form that matches the subject in the full sentence. Choice C.