Can you answer this by reading only the first 3 words of each answer choice?
Recently documented examples of neurogenesis, the production of new brain cells, include the brain growing in mice when placed in a stimulating environment or neurons increasing in canaries that learn new songs.
A. the brain growing in mice when placed in a stimulating environment or neurons increasing in canaries that
B. mice whose brains grow when they are placed in a stimulating environment or canaries whose neurons increase when they
C. mice’s brains that grow when they are placed in a stimulating environment or canaries’ neurons that increase when they
D. the brain growth in mice when placed in a stimulating environment or the increase in canaries’ neurons when they
E. brain growth in mice that are placed in a stimulating environment or an increase in neurons in canaries that
Here the answer is E. Let me show you how.
This is a split sentence. Basically in the form of [main sentence, description, main sentence]
Just take out the description in the middle and read it like this:
Recently documented examples of neurogenesis include [A] or .
From this alone, you should be able to eliminate (A), (B), and (C) just be reading the first three words of each answer choice.
(A): the brain growing
(B): mice whose brains
(C): mice’s brains
None of these work because they are not structured correctly as examples.
(D) and (E) are closer to what we want–either “the brain growth” or “brain growth”
The only difference between (D) and (E) is “when placed” versus “that.”
“When placed” seems to suggest a more specific condition whereas “that” seems more general and a description of a state of being–more of what we’re looking for.
Also, if you were to guess–choose the shorter answer choice–the one with fewer words—that would be (E).
Either way, the one you want here is (E) because it correctly begins with “brain growth in mice”–which is an example of a documented example of neurogenesis. And it’s consistent with the second part of the sentence.
Therefore, the answer is (E).