Scientist: In our study, chemical R

A free, expert breakdown of this official LSAT Logical Reasoning question.

TopicsRole

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Stimulus

Scientist: In our study, chemical R did not cause cancer in laboratory rats. But we cannot conclude from this that chemical R is safe for humans. After all, many substances known to be carcinogenic to humans cause no cancer in rats; this only via long-term exposure and rats are short lived.

What this question is testing

Role

Your task

Break the argument into its conclusion and evidence, then do exactly what the question stem asks with that structure.

Common trap

Answers that sound relevant to the topic but don't connect to the argument's actual reasoning.

Winning move

Predict what a right answer must do, then test each choice against the conclusion-evidence gap.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question

Which one of the following most precisely describes the role played in the scientist's argument by the statement that chemical R did not cause

Answer choices

Opposite2% picked this
It is cited as evidence against the conclusion that chemical R is
This sentence would be evidence for the idea that R is safe for humans.
2%
Bad Conclusion Match14% picked this
It is advanced to support the contention that test results obtained from laboratory rats cannot
The third sentence is advanced to support the contention that test results about rats cannot always / cannot immediately be extrapolated to humans. The first sentence is just a test result. The author brings it up because she knows that it will tempt people into extrapolating to humans.
14%
Trap4% picked this
It illustrates the claim that rats are too short lived to be suitable as test subjects for the carcinogenic properties of substances
Unmentioned / Out of Scope: “too short to be suitable” There is no claim that rats live too short to be suitable test subjects. We might make that inference upon reading the final claim in the argument, but the argument never makes that claim.
4%
Opposite2% picked this
It is used as evidence to support the hypothesis that chemical R causes cancer in
This claim would be evidence for the idea that R does not cause cancer in humans. Other claims in the argument help us realize that this first claim doesn’t prove R is safe for humans, but this claim isn’t supporting the hypothesis that R causes cancer in humans.
2%
Correct78% picked this
It is cited as being insufficient to support the conclusion that chemical R is
Why this is right
Our author’s conclusion says about this claim that “we cannot conclude from [this claim] that R is safe for humans”. So, yes, this claim was cited as being insufficient to support a conclusion that R is safe for humans. This is the only answer that correctly avoids premise language (it supports / it’s evidence / it illustrates) and gives us counterpoint language (it is cited as insufficient).
Skill tested: Role · how this choice captures the argument's function is the move to repeat next time.
78%

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