PrepTest 156

[lcid:3721] Prep Test 156 LSAT — Logical Reasoning — S2 Logical reasoning

Question prompt

Mr. Xu: The arctic Remaining source text redacted.
Why the credited answer is right

Credited answer: A

The notes below walk through why it fits the stem and how to eliminate the rest.

Argument or Facts

Argument

Valid or Flawed

Flawed

Strategy Overview

Argument or facts? Always argument, so identify premises and conclusions to argument Paraphrase how the argument uses its support to reach its conclusion
Checking to see if a common argumentative strategy (analogy, eliminating alternatives, generalizing from a sample/inductive reasoning, applying a principle, drawing an absurd conclusion) is very helpful Sometimes the argument is flawed, so the correct answer could describe a common fallacy

Answer Anticipation

When a question asks how one speaker's "response proceeds," it's a Methods of Reasoning question. So, it's our job to determine the argumentative strategy Ms. Yerky uses to respond to Mr. Yu's argument. Let's start by understanding the premises and conclusions of the two speakers' arguments. Mr. Xu argues that a hibernating arctic squirrel's blood temperature must contain a substance that prevents freezing at water's freezing temperature. To support this, Mr. Xu points out that the squirrel's blood temperature falls below water's freezing temperature but the blood never freezes, even though its blood is mostly water. Ms. Yerky responds that the arctic squirrel's blood doesn't contain a substance that prevents freezing at water's freezing temperature, as studies show that any animal's blood freezes at water's freezing temperature. After breaking down the premises and conclusions of both arguments, we want to think about how Yerky's argument relates to Xu's. What does Yerky take issue with in Xu's argument? And how does Yerky undermine that part of Xu's argument? Obviously, Yerky disagrees with Xu's conclusion — that the arctic squirrel's blood contains a substance that prevents freezing at water's freezing temperature. Yerky concludes that this isn't true. But Yerky supports her conclusion in an unusual way — she argues that the squirrel's blood freezes at the same temperature as water. Essentially, she disagrees with part of his conclusion — that the arctic squirrel's blood doesn't freeze at water's freezing temperature. This opens up a whole new mystery that test-makers probably hope we'll get distracted by. (Why do squirrels' blood not freeze? Or is Xu wrong about that?) But for Methods of Reasoning questions, we don't need to inquire — we just need to describe. And we've noted that Yerky undermines Xu's conclusion with evidence that is inconsistent with the conclusion Xu draws. Let's look for that in the answer choices.

Answer choices

  1. A
    presenting evidence that supports Remaining source text redacted.
    Why choice A matches the stem

    This is exactly what we anticipated, so we can select (A) confidently and advance to the following question. Yerky's evidence is that the arctic squirrel's blood freezes at the same temperature as water. Xu concludes that the arctic squirrel's blood has a substance that keeps it from freezing at water's freezing temp. But Yerky's evidence supports an entirely different conclusion — that arctic squirrel's blood can't contain a substance that prevents it from freezing at water's freezing temp because the blood actually freezes at that temp. So, it's accurate to say that Yerky's evidence supports a conclusion that's inconsistent with Xu's conclusion.

  2. B
    showing that the evidence Remaining source text redacted.
    Why choice B is not credited

    This doesn't match what we anticipated, so we can quickly eliminate it. Besides, Yerky never suggests that the means Xu used to collect his evidence was unreliable. That would require her to say that Xu's evidence relied on flawed studies, unreliable samples, or something like that.

  3. C
    offering an alternative explanation Remaining source text redacted.
    Why choice C is not credited

    This isn't what we anticipated, so let's cross it off. Besides, Yerky never explains why the squirrel's blood doesn't freeze at water's freezing temperature. We don't even know if Yerky agrees that the squirrel's blood doesn't freeze at that temp!

  4. D
    showing that a key Remaining source text redacted.
    Why choice D is not credited

    This isn't the same as our anticipation, so we can get rid of (D). Besides, Yerky doesn't take issue with the ambiguity of any of Xu's terms. That would require Yerky to discuss how at least one of the words in Xu's argument can mean more than one thing and that Xu exploits this ambiguity to make his argument sound better.

  5. E
    showing that the evidence Remaining source text redacted.
    Why choice E is not credited

    This isn't aligned with our anticipation, so let's toss (E) out. Besides, Yerky doesn't take issue with the relevance of Xu's evidence. In fact, Xu's evidence addresses all of the topics his conclusion raises, so Xu's evidence certainly has a bearing on the point at issue.

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