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(See the complete passage discussion here: lsat/viewtopic.php?t=14646)
Must Be True. The correct answer choice is (E)
In approaching this Must Be True question, we need to eliminate responses that are contrary to the facts
and inferences within the passage.
Answer choice (A): This answer choice states that nerve cells produce anti-NGF, and is therefore
unsupported by the passage, which never indicates precisely where anti-NGF is produced.
Answer choice (B): This choice asserts that cells not affected by NGF are less numerous than those
affected by NGF, and that the different cells have the same qualities. While the passage does support the
idea that there are different types of cells, not all of which are affected by NGF, but no further detail is
offered as to similarities or quantitative comparisons.
Answer choice (C): The passage does suggest that a significant number of nerve cells probably die off
in the process of an organism’s development. However, since the passage never offers any information
about the relative number of surviving cells, the conclusion that “few” cells are needed is unsupported.
Answer choice (D): Nothing in the passage indicates that some nerve cells have the capacity to change
into other types of living tissue, so this answer choice is incorrect.
Answer choice (E): This is the correct answer choice, as it is supported by the discussion in the
second paragraph. The passage states that an embryo initially produces more nerve cells than needed, and that the extra cells die off, which already supports the idea that the embryo produces nerve cells that
do not end up connecting to anything. Furthermore, the second paragraph indicates that NGF governs
the process by which some nerve cells develop and others die off (lines 14-26), and the third paragraph
explains, in detail, that NGF is the causal factor that helps direct nerve cells toward target cells. It is
reasonable to conclude that since some nerve cells will die off, they do not receive NGF, and do not
connect with target cells.