LSAT Explanation PT 28, S3, Q13: A recent study concludes that prehistoric

LSAT Question Stem

Which one of the following, if true, would most help to resolve the dispute described above in favor of one party to it? 

Logical Reasoning Question Type

This is a Paradox question. 

Correct Answer

The correct answer to this question is E. 

LSAT Question Complete Explanation

First, let's analyze the passage. There are two studies with conflicting conclusions about prehistoric birds. One study concludes that prehistoric birds were cold-blooded based on the existence of growth rings in their bodily structures, which are thought to be found only in cold-blooded animals. The other study disputes this view, concluding that prehistoric birds were warm-blooded due to the presence of dense blood vessels in their bones, which suggests that they were active creatures and therefore had to be warm-blooded.

The question type is a Paradox question, and we are asked to find an answer that would help resolve the dispute between the two studies in favor of one party.

Now let's discuss each answer choice:

a) Some modern warm-blooded species other than birds have been shown to have descended from cold-blooded species.

- This answer choice does not directly address the dispute about prehistoric birds being cold-blooded or warm-blooded. It only provides information about other species' evolution, which is not relevant to the specific dispute at hand.

b) Having growth rings is not the only physical trait of cold-blooded species.

- This answer choice does not help resolve the dispute, as it only states that there are other traits of cold-blooded species. It does not address the presence of dense blood vessels or provide any information that would strengthen one study's conclusion over the other.

c) Modern birds did not evolve from prehistoric species of birds.

- This answer choice is not relevant to the dispute, as the dispute is about whether prehistoric birds were cold-blooded or warm-blooded, not their relationship with modern birds.

d) Dense blood vessels are not found in all warm-blooded species.

- This answer choice weakens the argument that dense blood vessels are indicative of warm-bloodedness, but it does not strengthen the argument for cold-bloodedness or provide a clear resolution to the dispute. It only states that not all warm-blooded species have dense blood vessels, which does not necessarily mean that prehistoric birds with dense blood vessels were cold-blooded.

e) In some cold-blooded species the gene that is responsible for growth rings is also responsible for dense blood vessels.

- This answer choice helps resolve the dispute in favor of the cold-blooded conclusion. It shows that the presence of dense blood vessels, which was thought to be indicative of warm-bloodedness, can also be found in cold-blooded species due to a gene responsible for both growth rings and dense blood vessels. This means that prehistoric birds with dense blood vessels could still be cold-blooded, thus strengthening the cold-blooded argument and weakening the warm-blooded argument.

The correct answer is E.