LSAT Explanation PT 20, S4, Q23: Garbage dumps do not harm wildlife.

LSAT Question Stem

Each of the following statements, if true, casts doubt on the argument EXCEPT: 

Logical Reasoning Question Type

This is a Weaken question. 

Correct Answer

The correct answer to this question is D. 

LSAT Question Complete Explanation

First, let's analyze the argument in the passage. The conclusion of the argument is that "garbage dumps do not harm wildlife." The premise supporting this conclusion is the evidence from the Masai-Mara reserve in Kenya, where baboons that use the garbage dumps on the reserve as a food source mature faster and have more offspring than baboons that do not scavenge on garbage.

To make this more relatable, imagine two groups of rabbits living in a park. One group eats from a pile of discarded vegetables, and they grow bigger and have more babies than the other group that doesn't eat from the pile. The argument is claiming that since the rabbits eating the discarded vegetables are doing better, the pile of discarded vegetables isn't harmful to the animals in the park.

An "Evaluate" question for this argument would be, "Are there any other factors that could be causing the observed differences in maturity and offspring numbers between the two groups of baboons?"

Now, let's discuss the question type and the answer choices. This is a Weaken question, which means we are looking for an answer choice that casts doubt on the argument. However, this is an "except" question, so we need to identify the one answer choice that does NOT weaken the argument.

a) This answer choice weakens the argument because if the baboons that feed on the garbage dump are of a different species from those that do not, it undermines the comparison between the two groups. The differences in maturity and offspring numbers could be due to genetic factors rather than the garbage dump.

b) This answer choice weakens the argument because if the life expectancy of baboons that eat garbage is significantly lower than that of baboons that do not eat garbage, it suggests that there might be harmful effects of eating garbage that were not considered in the argument.

c) This answer choice weakens the argument because if the cholesterol level of garbage-eating baboons is dangerously higher than that of baboons that do not eat garbage, it indicates a potential harm to the health of the garbage-eating baboons.

d) This is the correct answer because it does not weaken the argument. The population of hyenas that live near unregulated garbage landfills doubling in the last two years has no direct harmful effect on the argument. We don't have enough information about the hyenas' behavior or population growth to determine if this is a negative or positive effect.

e) This answer choice weakens the argument because if the rate of birth defects for the baboon population on the reserve has doubled since the first landfills were opened, it suggests that the garbage dumps might be causing harm to the wildlife after all.

In conclusion, the correct answer is D, as it is the only answer choice that does not cast doubt on the argument.