LSAT Question Stem

Which one of the following, if true, does most to explain why the water of Lake Laberge currently contains high levels of toxaphene? 

Logical Reasoning Question Type

This is a Paradox question. 

Correct Answer

The correct answer to this question is A. 

LSAT Question Complete Explanation

The passage presents a paradox: Lake Laberge in Canada has high levels of the pesticide toxaphene, even though it was banned in North America in the early 1980s. Our task is to find an answer choice that helps explain this paradox.

Let's briefly analyze the passage. Toxaphene is a pesticide that was banned in North America in the early 1980s, but it is still present in high levels in Lake Laberge. This is puzzling because we would expect the levels of a banned substance to decrease over time.

Now, let's go through the answer choices:

a) Levels of pesticides in the environment often continue to be high for decades after their use ends.

This answer choice provides a plausible explanation for the paradox. If pesticide levels can remain high for decades after their use ends, it is possible that the high levels of toxaphene in Lake Laberge are a result of its previous use in North America before the ban. This is the correct answer.

b) Lake Laberge's water contains high levels of other pesticides besides toxaphene.

While this answer choice tells us that there are other pesticides present in Lake Laberge, it does not explain why the levels of toxaphene specifically are high. As JinZ551 pointed out, the presence of other pesticides is irrelevant to the paradox.

c) Toxic chemicals usually do not travel large distances in the atmosphere.

This answer choice actually makes the paradox more puzzling. If toxic chemicals do not travel large distances in the atmosphere, it becomes even more difficult to understand how toxaphene, which is now only used in a few other parts of the world, could end up in Lake Laberge.

d) North American manufacturers opposed banning toxaphene.

This answer choice is irrelevant to the paradox. Whether manufacturers opposed the ban or not does not provide an explanation for the high levels of toxaphene in the lake. What matters is whether they complied with the ban.

e) Toxic chemicals become more readily detectable once they enter organisms the size of fish.

This answer choice only tells us that toxaphene becomes more detectable in certain organisms, but it does not explain why the levels are high in the lake. It fails to address the paradox.

In summary, the correct answer is choice A, as it provides a plausible explanation for the paradox by stating that pesticide levels can remain high for decades after their use ends. This could account for the high levels of toxaphene in Lake Laberge despite its ban in North America.