Evaluate—CE. The correct answer choice is (D)
The key to solving this Evaluate the Argument question is to get a solid read on the stimulus, so let's begin by reviewing what is said by the author, starting with the two premises that open the stimulus:
- European wood ants use a specific resin in their nests. This resin is also a natural disinfectant that kills bacteria that harms wood ants.
So far, we just have some basic facts about these ants and their use of the resin, neither of which is too difficult to follow. Based on these two facts, the author jumps to the following conclusion:
- The reason the wood ants use this resin is probably because of the disease protection it provides.
This conclusion is causal in nature ("came about"), although it reflects a more modern LSAT language usage and drops the certainty level down to "probably." Regardless, the author is saying the cause of the ants originally using the resin is because it protects them from disease.
The question stem is an Evaluate the Argument, which is a rarer type on the LSAT. That means that if you don't recall how these work, it's easy to get tripped up. In this case, we want an answer that helps us evaluate whether that conclusion is true or false, and so we should be looking for a statement or question that focuses on the resin, specifically whether it is the cause or not.
Answer choice (A): The stimulus is careful to mention that the use of resin "came about" in the conclusion, and so the focus is on the initial use of resin, and not its long-term properties.
Answer choice (B): At first there is a tendency to read into this answer, and think it might having something to do with various ant disease patterns that might be greater in winter or summer, but the problem is that there is never enough information to assess whether the season makes a difference. If the answer is "yes" to this question, then it could simply be a product of when the resin is available from the trees, and if the answer is "no," that doesn't have any effect either (at least not one we can knowingly determine). Since differing response to the Variance Test questions yield no difference in our evaluation, this answer choice is incorrect.
Answer choice (C): This question as stated does not have an impact on whether the cause of the resin use was the disinfectant properties, mainly because we don't know whether the resin kills the bacteria that attack other ant species aside from the European wood ants.
Answer choice (D): This is the correct answer. The argument concludes that the disease-protection aspect of the resin is why the ants first started using it, but if the resin affords structural benefits, then that may be an alternate reason the ants first started using the resin. If so, knowing whether this was the case would help assess the argument. If there are structural benefits as described, the argument would be weakened, and if not, then the argument would be strengthened. Those yes/no answers provide different evaluations of the strength of this argument, meaning this answer passes the Variance Test and is correct.
Answer choice (E): The focus is on the ants usage of resin, and so information about how the resin developed and is used by conifer trees is not helpful.