LSAT 126 – Section 1 – Question 20

LSAT 126 - Section 1 - Question 20

October 2008

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Question
QuickView		 Type Tags Answer
Choices		 Curve Question
Difficulty		 Psg/Game/S
Difficulty		 Explanation
PT126 S1 Q20
+LR
Flaw or descriptive weakening +Flaw
Lack of Support v. False Conclusion +LSvFC
A
79%
164
B
4%
156
C
6%
157
D
7%
158
E
4%
153
143
151
159
 +Medium 146.126 +SubsectionMedium

A study of rabbits in the 1940s convinced many biologists that parthenogenesis—reproduction without fertilization of an egg—sometimes occurs in mammals. However, the study’s methods have since been shown to be flawed, and no other studies have succeeded in demonstrating mammalian parthenogenesis. Thus, since parthenogenesis is known to occur in a wide variety of nonmammalian vertebrates, there must be something about mammalian chromosomes that precludes the possibility of parthenogenesis.

A
takes for granted that something that has not been proven to be true is for that reason shown to be false
The author assumes that because parthenogenesis has not been proven to occur in mammals, that it does not occur in mammals. This is flawed because it’s possible parthenogenesis. does occur in mammals, even if it hasn’t yet been proven.
B
infers that a characteristic is shared by all nonmammalian vertebrate species merely because it is shared by some nonmammalian vertebrate species
The author states that parthenogenesis is known to occur in a “wide variety” of nonmammal vertebrates. That doesn’t mean the author believes parthenogenesis ocurs in “all” nonmammalian vertebrates.
C
rules out an explanation of a phenomenon merely on the grounds that there is another explanation that can account for the phenomenon
The author doesn’t point to an alternate explanation of parthenogenesis. Also, the issue is whether parthenogenesis occurs in mammals, not what explains the phenomenon of parthenogenesis.
D
confuses a necessary condition for parthenogenesis with a sufficient condition for it
There are no necessary or sufficient conditions for parthenogenesis described in the premises or the conclusion. So there cannot be a confusion of a necessary condition for parthenogenesis with a sufficient condition.
E
assumes that the methods used in a study of one mammalian species were flawed merely because the study’s findings cannot be generalized to all other mammalian species
The claim that the study’s methods were flawed is a premise. We don’t know why the author believes the study’s methods were flawed, so we cannot say the author assumed anything regarding why the studies were flawed.

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LSAT PrepTest 126 Explanations

Section 1 - Logical Reasoning

Section 2 - Reading Comprehension

Section 3 - Logical Reasoning

Section 4 - Logical Reasoning

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