#3 - Concept Reference, Must Be True

[Administrator]

Complete Question Explanation
(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.

[T.B.Justin]

• The author uses “form” and “behavior” when discussing the strict constructionist VP; does “form” mean anything that is not-behavior for example, physical appearance, structure and are these attributes of “form”, and “behavior” mean not-form as in internal characteristics and reproductive capability and are these attributes of “behavior.”

[Claire Horan]

Hi T.B. Justin,

Thanks for your question!

Here, "form" means, roughly, "physical attributes." "Behavior" is not meant as the opposite of "form" and means what you think it means: the way an animal acts. Accordingly to the author, form and behavior are both adapted through natural selection, as explained in lines 14-15. Generally, reading comprehension passages will use words in their everyday sense or define them for you, so look carefully for a definition when in doubt. Definitions will often be offset by commas or dashes. Other times, jargon words will be used in a separate sentence, either before or after the concept is explained.

I hope this explanation helps, but I am also still curious:

How did this confusion about the definitions impact your strategy for this question?

[T.B.Justin]

I recently started focusing on RC, and practicing identifying VPs', tone, premise and conclusion, structure, and main point; I am studying with the memory method at the moment.

Most of the questions I am getting incorrect is because of lack of understanding. I am not yet familiar with the flow of this section especially structure.

So, I was just handling the thoughts that were coming to me when I was reviewing this passage (delayed blind review process).

Thanks for engaging it helps me significantly!

Edit: I couldn't recall what the author's claim was on what most genetic changes are without looking back through the passage.