Logical ReasoningDifficulty: Medium

PT115 S4 Q18 Explanation

Foster: Many species of extremely

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

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Stimulus

Foster: Many species of extremely large North American mammals became extinct during the last ice age, which was also the time of the first human migration to North America. These species wrought by this human migration.

Fisch: Those extinctions were caused by the dramatic shift to a harsher climate. The climate changed so rapidly could not adapt.

What this question is testing

Strengthen

Your task

Find the choice that makes the argument's conclusion more likely to be true.

Common trap

Answers that are consistent with the argument but add no real support, or that strengthen a claim the argument doesn't make.

Winning move

Locate the gap between evidence and conclusion, then pick the choice that closes it.

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

The question
18.

Which one of the following, if true, most strengthens

Answer choices

  1. Weakens4% picked this

    Similar species living in parts of the world where there were dramatic changes in climate

    This hurts the plausibility of Fisch's explanation by providing Cause w/o Effect data points. Fisch thought that dramatic climate shifts were the Cause of extinctions, the Effect. This answer is providing data points where the Cause was present (there were dramatic changes in climate) but the Effect was absent (no extinctions).

  2. No Impact13% picked this

    Most of the mammals that survived in North America migrated from Asia at the same time

    This has more to with Foster's migration explanation, but it doesn't really strengthen or weaken either person's explanation. If anything, it helps Foster's explanation sound more plausible. If most of the surviving mammals were ones that migrated with humans (and thus were already used to them), that helps support the idea that the mammals in North America (who weren't used to living with humans until the humans migrated there) were disturbed by the arrival of humans.

  3. Strengthens Foster3% picked this

    Human migration to other previously isolated areas has resulted in mammal

    This helps the plausibility of Foster's hypothesis that migrations caused the extinctions. It's attesting to the fact that human migration to a new area often results in local species going extinct.

  4. Strengthens Foster0% picked this

    Archaeological evidence reveals that the human migrants had a number of different kinds

    This helps the plausibility of Foster's hypothesis that migrations caused the extinctions. It's saying that as these new humans arrived in North America, they came with lots of large weapons that could have been capable of killing the large mammals who went extinct.

  5. Correct80% picked this

    The huge size of the mammals made it difficult for them to migrate the great

    Why this is right

    This helps the plausibility of Fisch's hypothesis that dramatic shifts in climate are what caused the extinctions. It makes more sense why a super large mammal could be screwed by a dramatic shift in climate: they have a hard time migrating a great distance because of how big they are, so they couldn't run away from the new, bad climates and find a milder environment.

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

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