LSAT 148 | Section 4 | Logical Reasoning: Q22

LR Question 22 Explanation

QUESTION TEXT: Scientists once believed that the oversized head…

QUESTION TYPE: Argument Evaluation

CONCLUSION: It is wrong to think that the T rex evolved it’s oversized head, tiny limbs, etc in order to deal with the T rex’s massive size.

REASONING: We found an earlier dinosaur that had all those features, but was much smaller.

ANALYSIS: I first thought this was a question about evolution. Meaning that the earlier dinosaur showed that the other dinosaur had evolved the features first, and been small, and then passed the features on to the eventual T rex.

But I realized this actually doesn’t really matter. The earlier dinosaur doesn’t necessarily have to be a relative. Instead, its mere existence would show that there are reasons other than size for a dinosaur to have characteristic T rex features. That would then suggest that the T rex evolved those features for a different reason.

___________

1. It doesn’t matter if the head size ratio was exactly the same. Having a head that was oversized is enough, even if the ratio is mildly different.
2. CORRECT. This is highly relevant. If the newly discovered dinosaur was a baby, then that would be an alternate explanation for its small size. The adult version might be similar in size to an adult T rex.
3. Who cares? If there was a dinosaur that was 20% bigger and also had the same characteristic features, that wouldn’t affect the argument.
4. When I first saw this answer, I thought this seemed relevant. But I knew B was better, so I thought about it a while. You can read my thoughts in more detail in the analysis section above. But in short, even if the dinosaur were unrelated, it would still prove that tiny dinosaurs might develop characteristic T rex features for reasons other than accommodating size.
5. This isn’t very relevant. The dinosaur was tiny, so we would expect it didn’t prey on large species. Its only relevance is that it showed that tiny species could evolve characteristic T-rex features.

Recap: The question begins with “Scientists once believed that the oversized head,”. It is a Argument Evaluation question. To practice more Argument Evaluation questions, have a look at the LSAT Questions by Type page.