Question a-spec

3.2 Form, Structure, and Sense - Modifier placement and clarity
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A species of Byropsis algae produces toxins to avoid being eaten by predators. However, in some cases, the toxins the organism uses to protect itself from predation actually blank its attractiveness to predators. The Hawaiian sea slug, for example, not only tolerates Byropsis toxins but actually uses them for protection in the same way the algae does.

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

A.

is increasing

B.

increase

C.

increases

D.

has increased

A species of Byropsis algae produces toxins to avoid being eaten by predators. However, in some

Hard-difficulty · SAT Reading & Writing · Form, Structure, and Sense — Modifier placement and clarity. Read the question above, select your answer, and check the full explanation below to understand exactly why the correct choice works.

Answer explanation

Choice B is the best answer. The convention being tested is subject-verb agreement. The plural verb "increase" agrees in number with the plural subject "toxins."

Choice A is incorrect because the singular verb "is increasing" doesn’t agree in number with the plural subject "toxins." Choice C is incorrect because the singular verb "increases" doesn’t agree in number with the plural subject "toxins." Choice D is incorrect because the singular verb "has increased" doesn’t agree in number with the plural subject "toxins."