SAT OwlQuestion bank / Form, Structure, and Sense
The small, shrimp-like crustaceans known as krill, which feed on phytoplankton in the cold waters around Antarctica, ______ a primary food source for many whales, seals, and penguins.
Which choice completes the text so that it conforms to the conventions of Standard English?
are
is
has been
was
Show answer and explanation
Answer: A
The subject is "crustaceans," which is plural. The clause "which feed on phytoplankton..." only describes them. A plural subject takes the plural verb "are."
Choice B may seem to agree with "Antarctica" or "krill," but the subject is the plural noun "crustaceans."
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