Logical reasoning PrepTest 137 · Section 3 · Question 19

Incorrect. Since the argument doesn't test or conclude anything about Theory 1, this answer is out of scope. This argument is only about the viability of Theory 2, not Theory 1.

Incorrect. The conclusion is that something isn't the cause. And it's not based on a mere correlation—it's based on a study that showed something didn't work.

Incorrect. Nothing is established as being sufficient for sea butterflies to avoid predation—in fact, the entire argument is meant to analyze what is responsible for it, and the only conclusion it reaches is that the chemical compounds in the sea butterflies aren't a sufficient explanation (they're not any explanation, in fact).

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Errors in Reasoning

Stimulus Summary:
Theory 1 – Sea butterflies use their appearance to avoid predation
Theory 2 – Sea butterflies produce chemical compounds to avoid predation
Study – Each compound was added individually to food pellets, and predators ate each one
Conclusion – Theory 2 is wrong

Answer Anticipation:
First, note that Theory 1 is completely irrelevant to this argument. The conclusion isn't that Theory 1 (the appearance theory) is correct nor does it mention appearance at all, and the study doesn't test that theory in any way, so we shouldn't consider any answer choice that raises it.

Now, on to the actual argument! Theory 2 states that the various chemicals produced by the sea butterflies are what prevent them from being preyed upon. However, each of these compounds individually failed to stop predators from eating food. So none of these compounds can be individually responsible for the avoidance of predation.

However, in the wild, these chemicals aren't individually present in the sea butterflies—they're all present together. The study didn't test these chemicals in combination, and so it can't validly rule them out as the means by which sea butterflies avoid predation. The correct answer should highlight that just because the chemicals don't work individually, that doesn't mean they don't work when combined. (If you viewed this as a jump from the parts to a whole, then there's nothing wrong with the way you're thinking.)

Answer Explanation:
The set in question is the set of chemical compounds. Each individually had no effect on predators, but that doesn't mean that they don't have an effect when all combined. It's possible they become poisonous when and only when all are present!

Key Takeaway:
Sea butterflies are cool. Google them!

On a more serious note, when a study is done in non-natural settings (e.g., extracting chemicals and putting them in food pellets), then it has to mirror the natural setting as much as possible. If the study is skewed in some way, then the difference between reality and the study is likely going to be highlighted as a flaw in the argument.

And, finally, there are times the LSAT throws something into the stimulus to distract you. Here, since Theory 1 was never brought up again in the study or the conclusion, you should disregard it as relevant and immediately defer on any answer that brings it up.

Incorrect. This answer is the circular reasoning answer, but no premise states that the compounds aren't responsible for the avoidance of predation, so this answer is wrong.