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(See the complete passage discussion here: lsat/viewtopic.php?t=14060)
The correct answer choice is (D)
Here, the question references the third paragraph, in which the Author discussed mutations of genetic material. In this paragraph, the author explained that “neutral, nonadaptive changes account to a large extent for the evolution of DNA.” In fact, most mutations are nonadaptive and are “not explainable by natural selection.”
Answer choice (A): The Author told us in the third paragraph that some harmful genetic attributes are weeded out, and so are not passed on to subsequent generations. However, the Author did not say that the majority of mutations are similarly weeded out. This answer choice improperly combine’s the Author’s claim that some genetic attributes are weeded out with the claim that most mutations are nonadaptive.
Answer choice (B): Here, the answer choice misdirects our attention to the fourth paragraph, in which the author discussed the mass extinction of the dinosaurs. However, the mass extinction evidence was a separate line of argumentation from the discussion of genetic mutations in the third paragraph.
Answer choice (C): The Author did not discuss this quantitative comparison between the percentage of mutations that affect species’ appearance and the percentage that affect their behavior.
Answer choice (D): This is the correct answer choice. The Author states that most genetic changes are neutral and nonadaptive, meaning that they have no effect on reproductive success.
Answer choice (E): As with answer choice (B), this choice attempts to misdirect your attention to the fourth paragraph discussion of dinosaurs and the smaller mammals. Again, the mass extinction evidence was distinct from the discussion of genetic mutation in paragraph three.