Logical reasoning PrepTest 104 · Section 1 · Question 11

Question prompt

A local chemical plant 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

Cause & Effect / Flawed Parallel Reasoning Questions

Stimulus Summary

Causal relationship - Pesticides can cause sterility in otters
Correlation - After a pesticide opened, otters sterility went up
Conclusion - The pesticides contaminated the river/caused the sterility

Answer Anticipation

This argument presents a wrinkle on a very common error in reasoning present on the LSAT - the Correlation/Causation flaw.
The argument has all of the elements of a traditional Correlation/Causation flaw - a correlative premise (“Soon after…”), and a causal conclusion (implied through the conclusion that assumes the pesticides are causing the sterility). However, it also has a causal premise, establishing that the pesticides can cause the sterility that was seen.
A causal premise can support a causal conclusion. However, in order to do so, the argument needs to establish that the cause is present. Here, there’s no indication that the pesticide is leaking into the river - just that it’s being produced nearby. There could be something else causing the sterility - maybe another plant opened up at the same time, or the pesticide plant is dumping a different chemical that can cause sterility.
This argument establishes a causal relationship, but it then relies on a correlation to conclude that the cause is present, so let’s find an answer that matches that.

Answer choices

  1. A
    The bacteria that cause Remaining source text redacted.
    Why choice A is not credited
    The conclusion here is comparative, whereas the stimulus isn’t, so there’s a comparison flaw present here missing from the stimulus. Additionally, the second premise here isn’t a correlation.

  2. B
    A diet low in Remaining source text redacted.
    Why choice B matches the stem
    This argument starts with a causal relationship (low-calcium diets causing drops in egg production). It then presents a correlation - the chickens were let out to forage, and they saw a drop in egg production. It finally concludes, based on this correlation, that the cause was present - that a diet low in calcium explains the drop in egg production. That has the same flawed pattern of reasoning as the stimulus, ignoring other potential causes of the drop in egg production, so this is the correct answer.

  3. C
    Animals that are undernourished Remaining source text redacted.
    Why choice C is not credited
    The second premise here establishes that the cause isn’t present, whereas the stimulus concludes that it is, so this argument isn’t parallel to the one in the stimulus.

  4. D
    Apes are defined by Remaining source text redacted.
    Why choice D is not credited
    There are no causal premises in this argument, so we can eliminate it.

  5. E
    The only animal that Remaining source text redacted.
    Why choice E is not credited
    The opening premise here is a conditional, so it has logic different from the stimulus, which was causal.

What this tests

Question analytics

Based on historical answer selection rates for this question.

Answer choice distribution

  1. A 5%
  2. B Credited 84%
  3. C 3%
  4. D 7%
  5. E 1%

Deeper help

Ask follow-ups on any step

Optional AI tutor mode will let you interrogate assumptions, compare answers, and drill weak patterns without leaving the page.

Human-written explanations stay primary; AI is an add-on when you want it.

Discussion

No threads yet—be the first to ask a question or share an approach.

View all discussions Start a discussion