LSAT Explanation PT 30, S2, Q22: The folktale that claims that a

LSAT Question Stem

Which one of the following is an assumption the argument requires in order for its conclusion to be properly drawn? 

Logical Reasoning Question Type

This is a Necessary Assumption question. 

Correct Answer

The correct answer to this question is E. 

LSAT Question Complete Explanation

This LSAT problem is a Necessary Assumption question, which means we are asked to identify an assumption that the argument relies on for its conclusion to be valid. The conclusion of the argument is that if rattlesnakes' rattles were not brittle, one could reliably determine a rattlesnake's age simply from the number of sections in its rattle. The premise supporting this conclusion is that one new section is formed each time a rattlesnake molts. Now, let's analyze each answer choice to determine the correct assumption.

a) Rattlesnakes molt exactly once a year.

This answer choice may seem tempting, but it is not necessary for the argument to hold. Even if rattlesnakes molt more or less than once a year, as long as the molting frequency is consistent, one could still determine the age based on the number of sections in the rattle.

b) The rattles of rattlesnakes of different species are identical in appearance.

The argument doesn't focus on the appearance of the rattles, but rather on the number of sections in the rattle. This assumption is not necessary for the argument to be valid.

c) Rattlesnakes molt more frequently when young than when old.

This answer choice suggests an irregular molting pattern, which would actually weaken the argument. If molting frequency changes with age, it would be more difficult to determine the age based on the number of sections in the rattle.

d) The brittleness of a rattlesnake's rattle is not correlated with the length of the rattlesnake's life.

This assumption is not necessary for the argument to be valid. The argument is about determining the age based on the number of sections in the rattle, not about the relationship between brittleness and the rattlesnake's life length.

e) Rattlesnakes molt as often when food is scarce as they do when food is plentiful.

This is the correct assumption. The argument relies on the idea that the molting frequency is consistent in order to determine the age based on the number of sections in the rattle. If the molting frequency varies depending on food availability, the argument would fall apart, as it would be difficult to accurately determine the age.

In conclusion, answer choice (e) is the correct assumption required for the argument's conclusion to be properly drawn. The molting frequency needs to be consistent for the argument to work, and this answer choice addresses a potential inconsistency in molting frequency and dismisses it.