Lucía Michel of the University of Chile observed that alkaline soils contain an insoluble form of iron that blueberry plants
cannot absorb, thus inhibiting blueberry growth. If these plants were grown in alkaline soil alongside grasses that aid in iron
solubilization, ______ Michel was determined to ﬁnd out.
could the blueberries thrive.
the blueberries could thrive.
the blueberries could thrive?
could the blueberries thrive?
Choice D is the best answer. The convention being tested is end-of-sentence punctuation. This choice correctly uses a
question mark to punctuate the interrogative clause “could the blueberries thrive,” which asks a direct question at the end of
the sentence.
Choice A is incorrect because a period can’t be used in this way to punctuate an interrogative clause, such as “could the
blueberries thrive,” at the end of a sentence. Choice B is incorrect because the context requires an interrogative clause. The
declarative clause “the blueberries could thrive” incorrectly indicates that it was known that the blueberries could thrive in
alkaline soil, whereas Michel had yet to ﬁnd this out. Choice C is incorrect because a question mark can’t be used in this way
to punctuate a declarative clause, such as “the blueberries could thrive,” at the end of a sentence.