LSAT 152 – Section 1 – Question 08

LSAT 152 - Section 1 - Question 08

November 2018

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Question
QuickView		 Type Tags Answer
Choices		 Curve Question
Difficulty		 Psg/Game/S
Difficulty		 Explanation
PT152 S1 Q08
+LR
Flaw or descriptive weakening +Flaw
Causal Reasoning +CausR
A
3%
154
B
0%
145
C
8%
153
D
87%
162
E
1%
154
137
144
152
 +Medium 148.23 +SubsectionMedium

Monarch butterflies must contend with single-celled parasites that can cause deformities that interfere with their flight. In populations of monarch butterflies that have not migrated, as many as 95 percent are heavily infected by the parasites, while less than 15 percent of those in migrating populations are infected. This shows that migrating allows monarch butterflies to avoid these parasites.

Summarize Argument: Phenomenon-Hypothesis

The author hypothesizes that migration allows monarchs to avoid the parasites. She supports this by saying that up to 95% of non-migrating monarch populations are infected, while less than 15% of migrating populations are infected. She also says the parasites can interfere with monarchs’ flight.

Identify and Describe Flaw

This is the cookie-cutter flaw of assuming that correlation proves causation. The author notes a correlation between migration and lower infection percentages and then concludes that migration causes monarchs to avoid infection. Her reasoning is flawed because she overlooks two key alternative hypotheses:

(1) The causal relationship could be reversed—maybe parasitic infections prevent monarchs from migrating, not the other way around.

(2) Another factor might cause certain populations to not migrate and to be more vulnerable to parasites.

A
monarch butterflies are unable to detect which areas are free from parasites

Migrating monarchs have a lower percentage of infections, but it doesn’t matter whether they can detect which areas are free from parasites. Even if the author did address this, it wouldn’t impact her conclusion that migration allows these monarchs to avoid parasites.

B
long migrations are no better protection from parasites than are short migrations

The author just concludes that migration allows monarchs to avoid the parasites; she never claims that long migrations are better than short ones. Even if long and short migrations are equally effective, this wouldn’t impact her conclusion.

C
populations of monarch butterflies that have not migrated are much larger than migrating populations

The author addresses the percentage of monarchs infected, not the number. Even if there are more non-migrating monarchs, it doesn't change the fact that they have a higher percentage of infections. The question of what causes this higher percentage still remains.

D
monarch butterflies infected with parasites are typically unable to migrate

The author overlooks the possibility that the causal relationship is reversed. Maybe the parasites cause monarchs not to migrate, rather than the other way around. After all, the author does say that the parasites can interfere with the monarchs’ flight.

E
populations of monarch butterflies tend not to migrate if they have stable food sources

Even if monarchs with stable food sources tend not to migrate, this doesn’t change the fact that these non-migrating populations have a higher percentage of infections. It also doesn’t affect the conclusion that migration helps the migrating monarchs to avoid the parasites.

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LSAT PrepTest 152 Explanations

Section 1 - Logical Reasoning

Section 2 - Logical Reasoning

Section 3 - Reading Comprehension

Section 4 - Logical Reasoning

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