Logical Reasoning

PT157 · S3 · Q11 Biologist: The evolutionary advantage

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

  • Save & drill this skill — build targeted practice sets from questions like this one

  • Video walkthroughs — watch every question solved step by step

  • 81 official LSATs — as questions, timed sections & full-length tests

Start practicing free

Biologist: The evolutionary advantage of sexual reproduction is that it increases the range of genetic variation in a species, which is an advantage for the species as a whole.

Conclusion (it follows that)

The sole reason that sexual reproduction has become the rule among both animals and plants is that natural selection has favored some entire species over others.

Evidence

The evolutionary advantage of sexual reproduction is that it increases the range of genetic variation in a species, which is an advantage for the species as a whole.

But an increased range of genetic variation in a species is not advantageous for any individual member of the species.

Evaluate

The word "however" in the second sentence indicates a pivot from the idea in the first sentence to a different, contrasting idea. In the final sentence, the phrase "it follows that" indicates that this final sentence contains a conclusion, supported by evidence in the previous sentences.

Goal

The statement quoted by the question stem is in the second sentence of the stimulus, which contains the argument's evidence or premise.

11.

The claim that an increased range of genetic variation in a species is not advantageous for any individual member of the species plays which one of the following roles in the biologist's argument?

  1. Correct

    It is a claim offered

    Why this is right

    The quoted statement is evidence — a claim that supports the conclusion. It establishes that genetic variation does not benefit individuals, which forces the explanation for sexual reproduction's prevalence to the species level. This directly supports the conclusion about species-level natural selection.

    Skill tested: Role · how this choice captures the argument's function is the move to repeat next time.

    65% picked this

  2. It is presented to raise

    Opposing Idea

    The quoted statement does not raise doubt about the conclusion — it supports it. By showing that genetic variation does not benefit individuals, it strengthens the case for species-level selection. It is an ally of the conclusion, not a challenger.

    5% picked this

  3. It is a claim that

    Opposing Idea

    The argument does not call the quoted statement into question — it embraces it as support for the conclusion. The argument builds upon this claim rather than attempting to undermine it.

    9% picked this

  4. It describes an observed phenomenon

    Conclusion

    The conclusion explains why sexual reproduction has become the rule — the "observed phenomenon" if there is one. But the quoted statement is about whether genetic variation benefits individuals, which is evidence, not the phenomenon being explained. The phenomenon the argument seeks to explain is the prevalence of sexual reproduction, described in the conclusion itself.

    17% picked this

  5. It is presented as the

    Conclusion

    The main explanation of why sexual reproduction prevails is in the conclusion: species-level natural selection. The quoted statement is not the explanation — it is evidence that leads to the explanation. It establishes that individual-level selection cannot explain sexual reproduction, which then supports the species-level explanation in the conclusion.

    5% picked this

Continue the review in LSAT Lab

Save this question, watch the video walkthrough, and drill similar questions in your LSAT Lab account.

Save and practice this skill
LSAT Lab

Turn this review into a targeted study plan.

Save this question, drill more like it, watch the video walkthrough, and track your progress in your LSAT Lab account.

Start practicing free