Logical reasoning PrepTest 112 · Section 4 · Question 4

Question prompt

A certain gene can 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

Question Type

Must Be True Questions

Stimulus Summary

Certain gene + Cigarette smoke = Cancer
Smokers who don’t have this gene stimulated get lung cancer just as frequently

Answer Anticipation

When we’re dealing with Must be True questions, we should always be on the lookout for the types of statements that the LSAT uses to build logical arguments. Here, we have two of them.
First, we get a causal relationship. A certain gene, when stimulated by cigarette smoke, causes lung cancer.
Second, we get a comparative relationship. Those smokers who have their gene stimulated and those who don’t have an equivalent risk of lung cancer.
Is there a way for us to combine these statements? Here, there is. If people with one cause of lung cancer are just as likely to get it as those without that factor, then there must be other factors that contribute to lung cancer risk. Let’s find an answer stating that.

Answer choices

  1. A
    stimulation of the gene Remaining source text redacted.
    Why choice A matches the stem
    This answer matches our anticipation. If people who don’t have their gene stimulated have the same risk of cancer as those who do, and we know that the gene being stimulated increases risk of lung cancer, the former group must have some other risk factor.
  2. B
    nonsmokers have as high Remaining source text redacted.
    Why choice B is not credited
    The stimulus doesn’t discuss nonsmokers, so this answer is out of scope.
  3. C
    smokers in whom the Remaining source text redacted.
    Why choice C is not credited
    The stimulus compares two groups and says that they have “as high a risk” of developing lung cancer, so this answer stating that one group is “more likely” to develop lung cancer is unsupported.
  4. D
    the gene is more Remaining source text redacted.
    Why choice D is not credited
    There’s no discussion of the gene being stimulated by other chemicals, or of the likelihood of other chemicals stimulating the gene, so this answer is out of scope.
  5. E
    smokers are less likely Remaining source text redacted.
    Why choice E is not credited
    Similar to (C), the stimulus discusses groups that have “as high a risk” of lung cancer as another, so this answer about one group being less likely than another is out of scope.

What this tests

Question analytics

Based on historical answer selection rates for this question.

Answer choice distribution

  1. A Credited 93%
  2. B 1%
  3. C 3%
  4. D 1%
  5. E 2%

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