LSAT 137 – Section 3 – Question 19

LSAT 137 - Section 3 - Question 19

October 2012

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Question
QuickView		 Type Tags Answer
Choices		 Curve Question
Difficulty		 Psg/Game/S
Difficulty		 Explanation
PT137 S3 Q19
+LR
+Exp
Flaw or descriptive weakening +Flaw
A
13%
161
B
6%
157
C
12%
157
D
67%
166
E
1%
153
148
157
166
 +Harder 146.416 +SubsectionMedium

Ecologist: One theory attributes the ability of sea butterflies to avoid predation to their appearance, while another attributes this ability to various chemical compounds they produce. Recently we added each of the compounds to food pellets, one compound per pellet. Predators ate the pellets no matter which one of the compounds was present. Thus the compounds the sea butterflies produce are not responsible for their ability to avoid predation.

Summarize Argument: Phenomenon-Hypothesis
The ecologist rejects a hypothesis that sea butterflies deter predators with chemicals they produce, citing an experiment where each chemical was tested one at a time and none was found to deter predators on its own.

Identify and Describe Flaw
This is an example of the part-to-whole fallacy because the ecologist ignores the possibility that, while no individual chemical appears to deter predators on its own, some combination of chemicals could do so when mixed together. The experiment only tested each chemical one at a time, though the chemicals would presumably all be present together in a living sea butterfly.

A
presumes, without providing justification, that the two theories are incompatible with each other
The argument doesn’t assume that the theories cannot both be true because it never assesses the theory about their appearance. The ecologist only rejects the chemical explanation.
B
draws a conclusion about a cause on the basis of nothing more than a statistical correlation
The argument never mentions a correlation. The experiment was meant to demonstrate that chemicals don’t produce the effect of deterring predators, but was flawed because it only tested chemicals one at a time.
C
treats a condition sufficient for sea butterflies’ ability to avoid predators as a condition required for this ability
There’s no sufficient condition for avoiding predators, nor does the ecologist claim that anything is necessary to avoid predators. The flaw is citing an experiment that isolated chemicals rather than testing them together.
D
infers, from the claim that no individual member of a set has a certain effect, that the set as a whole does not have that effect
This describes how the ecologist uses an experiment that shows that no individual chemical deters predators, but ignores the possibility that multiple chemicals could deter predators when mixed together.
E
draws a conclusion that merely restates material present in one or more of its premises
This describes circular reasoning, where an argument assumes its conclusion in one of its premises. The conclusion that compounds are not responsible for predator avoidance is not stated in the argument’s premises.

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LSAT PrepTest 137 Explanations

Section 1 - Reading Comprehension

Section 2 - Logical Reasoning

Section 3 - Logical Reasoning

Section 4 - Logical Reasoning

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