Official ExplanationDead plant matter creates coal through heat and pressure,
which produces chemical and physical changes, forces out oxygen, and replaces them with carbon deposits.
(A) which produces chemical and physical changes, forces out oxygen, and replaces them(B) which produces chemical and physical changes, forces out oxygen, and those are replaced (C) which produces chemical and physical changes, forces out oxygen, and to be replaced (D) which produces chemical and physical changes, forcing out oxygen, and to be replaced (E) which produces chemical and physical changes, forces out oxygen and replaces themAfter a quick scan over the question, it should be clear by now that this question deals with parallelism. Each verb needs to be written the same way, in the correct tense, for consistency within the sentence. Let’s see how each sentence stacks up:
(A) which
produces chemical and physical changes,
forces out oxygen, and
replaces them
This is
CORRECT. It has parallel structure; the verbs in the sentence use the same verb tense.
(B) which
produces chemical and physical changes,
forces out oxygen, and those are
replaced This is
INCORRECT. It is does not have parallel structure, the verb replaced is incorrect.
(C) which
produces chemical and physical changes,
forces out oxygen, and to be
replaced This is
INCORRECT. It is does not have parallel structure, the verb replaced is incorrect.
(D) which
produces chemical and physical changes,
forcing out oxygen, and to be
replaced This is
INCORRECT. It is does not have parallel structure, the verbs forcing and replaced are incorrect. In fact, none of them match!
(E) which
produces chemical and physical changes,
forces out oxygen
and replaces them
This is
INCORRECT. It does have parallel structure; however, it does not have the Oxford comma required by the GMAT.
There you have it - option A was the correct choice all along!NOTE:Thanks to
PS17198 for catching a typo in the original sentence/option A. Since that clearly threw off everyone this round, we're going to give anyone who attempted this question before the OA was posted a kudos. We will double-check all future questions from now on, and appreciate that you're keeping us honest!
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