LSAT 115 – Section 4 – Question 18

LSAT 115 - Section 4 - Question 18

December 2002

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Question
QuickView		 Type Tags Answer
Choices		 Curve Question
Difficulty		 Psg/Game/S
Difficulty		 Explanation
PT115 S4 Q18
+LR
Strengthen +Streng
Causal Reasoning +CausR
A
5%
157
B
17%
159
C
2%
153
D
0%
151
E
76%
163
126
143
160
 +Medium 146.173 +SubsectionMedium

Foster: Many species of extremely large North American mammals became extinct during the last ice age, which was also the time of the first human migration to North America. These species could not survive the dramatic changes wrought by this human migration.

Fisch: Those extinctions were caused by the dramatic shift to a harsher climate. The climate changed so rapidly that the species could not adapt.

Summarize Argument: Phenomenon-Hypothesis
Fisch hypothesizes that the extinctions were caused by a dramatic shift to a harsh climate. This shift happened too fast for the species to adapt.

Notable Assumptions
Fisch assumes that if species can’t adapt to climatic changes, those species will go extinct. She also assumes that the climate explanation is superior to the human migration explanation.

A
Similar species living in parts of the world where there were dramatic changes in climate did not become extinct.
This weakens Fisch’s argument. Climatic changes don’t invariably cause extinctions among the species in question.
B
Most of the mammals that survived in North America migrated from Asia at the same time as the humans migrated.
We don’t care when those mammals came to North America. We care about why they went extinct.
C
Human migration to other previously isolated areas has resulted in mammal species becoming extinct.
This supports the alternate hypothesis. We’re looking to strengthen Fisch’s hypothesis.
D
Archaeological evidence reveals that the human migrants had a number of different kinds of large weapons.
This weakly strengthens the alternate hypothesis. We’re looking to strengthen Fisch’s hypothesis.
E
The huge size of the mammals made it difficult for them to migrate the great distances to milder environments.
Large mammals went extinct because they couldn’t migrate quickly enough to milder climates after the climate shift. Since they also couldn’t adapt, they went extinct.

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LSAT PrepTest 115 Explanations

Section 1 - Reading Comprehension

Section 2 - Logical Reasoning

Section 3 - Reading Comprehension

Section 4 - Logical Reasoning

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