LSAT 155 | Section 2 | Logical Reasoning: Q3

LR Question 3 Explanation

QUESTION TEXT: Biologist: DNA analysis shows that Acacia heterophylla…

QUESTION TYPE: Strengthen

CONCLUSION: Seabirds probably caused the dispersal of the seeds.

REASONING: It’s implausible that the seeds floated to Reunion, since the seeds won’t germinate if they’re soaked and the trees grow near the mountain and not the shore. Seabirds sometimes carry seeds great distances.

ANALYSIS: This argument spends more time disproving the floating theory than it does supporting the seabird theory. We have a lot of evidence that they didn’t float, but the only support for the seabirds theory is that seabirds sometimes carry seeds. To strengthen the argument, we want more to show that the seabirds theory is true here.

___________

1. This doesn’t strengthen the argument at all. It provides some support for the floating theory, but that’s not what we’re trying to do.
2. CORRECT. If the same seabirds live in the mountains of both areas, and are known to carry seeds great distances, then it’s certainly plausible that that’s how the seeds got to Reunion.
3. This doesn’t do anything to help the argument. We don’t know anything about Australia, so it doesn’t provide support for our argument.
4. This doesn’t support the argument. Remember that the author is arguing for the seabird theory, not the floating theory.
5. This doesn’t strengthen the seabird theory, and the conclusion is that the seabird theory is probably correct. So we should not pick this one, since it doesn’t support the conclusion.

Recap: The question begins with ” Biologist: DNA analysis shows that Acacia heterophylla”. It is a Strengthen question. Learn how to master LSAT Strengthen questions on the LSAT Logical Reasoning question types page.