PrepTest 126
[lcid:3602] Prep Test 126 LSAT — Logical Reasoning — S3
Logical reasoning
Question prompt
Biologist: Many paleontologists have
Remaining source text redacted.
Why the credited answer is right
Credited answer: B
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
Errors in Reasoning Questions
Stimulus Summary
Paleontologists: Adapting to ice ages was responsible for the development of the human brain
Biologist: Other animals adapted to ice ages without their brain changing, so the paleontologists are wrong.
Answer Anticipation
This argument features a Biologist rebutting the view of “[m]any paleontologists,” so we should determine how she rebuts that view. To do so here, she brings up “most other animal species” that went through the same thing as humans but didn’t develop the adaptation that the paleontologists say was a response to that thing (the ice ages). In short, the Biologist brings up what she believes to be many counterexamples.
Whenever an argument relies on counterexamples, it’s important to figure out if the counterexamples actually disprove the initial view. And in this case, they don’t - just because other animals didn’t respond in a particular way to the difficulties of an ice age doesn’t mean that humans couldn’t have responded with brain development.
It’d be like saying that Ana got into her locked apartment by calling a locksmith, so Joe couldn’t have gotten into his locked apartment by breaking a window. The two situations are different, the people involved are different, and they could respond to the same difficulty with different methods.
Similarly, humans could have had one response to the stress of an ice age, while most other animals responded with other adaptations.
Answer choices
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AIt fails to address Remaining source text redacted.
Why choice A is not credited
The Biologist’s argument relies on comparing humans to other species, so this answer discussing a single species (“sufficient...in a species, necessary...in that species”) doesn’t properly reflect the argument. -
BIt fails to address Remaining source text redacted.
Why choice B matches the stem
This answer highlights the issue with using other species as a counterexample, since they could adapt to a given condition differently. It’s possible that the condition (ice age) can produce a change (brain development) in a species (human) even if it doesn’t do the same in other species. -
CIt overlooks the possibility Remaining source text redacted.
Why choice C is not credited
There’s no indication that the ice age was necessary to cause the evolutionary changes in the human brain - it’s possible that other difficult conditions could have caused it, as well. -
DIt presumes without warrant Remaining source text redacted.
Why choice D is not credited
The argument assumes that humans responded to the difficulties of the ice ages differently than most other species, but that doesn’t necessarily mean that they faced greater difficulties. -
EIt takes for granted Remaining source text redacted.
Why choice E is not credited
If anything, the paleontologists are making the correlation/causation jump, not the Biologist.