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- Wed May 17, 2017 2:34 pm
#34972
Complete Question Explanation
(See the complete passage discussion here: lsat/viewtopic.php?t=14154)
The correct answer choice is (B)
This Concept Reference/Purpose question asks us to explain why the author discusses primary
substances. Such questions almost always require a more thorough understanding of the context
in which the concept reference appears (which, in this case, is the first paragraph). Their answers
should generally be prephrased.
Answer choice (A): Although primary substances do play a vital role in processes of growth and
metabolism, the author does not discuss primary substances in order to provide this information.
The focus of the first paragraph, and of the passage as a whole, is on secondary substances and their
evolutionary significance to plants and insects.
Answer choice (B): This is the correct answer choice. Primary substances are discussed in the
first paragraph, and are neither mentioned nor alluded to later in the passage. Clearly, their mention
serves one purpose only: to distinguish them from secondary substances, and thus facilitate our
understanding of the latter.
Answer choice (C): Although a distinction is being made in the first paragraph, it is between primary
and secondary substances, not between two ways that insects have affected plant evolution.
Answer choice (D): It is the secondary, not the primary, substances that are diverse across various
species of plants. Furthermore, the author does not mention primary substances in order to highlight
their diversity.
Answer choice (E): There is no evidence that primary substances have evolved in response to
evolutionary pressure by insects. Insects were not even mentioned in the first paragraph, making this
answer choice easy to eliminate.
(See the complete passage discussion here: lsat/viewtopic.php?t=14154)
The correct answer choice is (B)
This Concept Reference/Purpose question asks us to explain why the author discusses primary
substances. Such questions almost always require a more thorough understanding of the context
in which the concept reference appears (which, in this case, is the first paragraph). Their answers
should generally be prephrased.
Answer choice (A): Although primary substances do play a vital role in processes of growth and
metabolism, the author does not discuss primary substances in order to provide this information.
The focus of the first paragraph, and of the passage as a whole, is on secondary substances and their
evolutionary significance to plants and insects.
Answer choice (B): This is the correct answer choice. Primary substances are discussed in the
first paragraph, and are neither mentioned nor alluded to later in the passage. Clearly, their mention
serves one purpose only: to distinguish them from secondary substances, and thus facilitate our
understanding of the latter.
Answer choice (C): Although a distinction is being made in the first paragraph, it is between primary
and secondary substances, not between two ways that insects have affected plant evolution.
Answer choice (D): It is the secondary, not the primary, substances that are diverse across various
species of plants. Furthermore, the author does not mention primary substances in order to highlight
their diversity.
Answer choice (E): There is no evidence that primary substances have evolved in response to
evolutionary pressure by insects. Insects were not even mentioned in the first paragraph, making this
answer choice easy to eliminate.