LSAT 111 | Section 1 | Logical Reasoning: Q16

LR Question 16 Explanation

QUESTION TEXT: On the basis of the available evidence, Antarctica has…

QUESTION TYPE: Main Conclusion

CONCLUSION: The Antarctic ice sheet must have temporarily melted three million years ago.

REASONING: Some fossils were found in Antarctica that previously were only found on the sea floor. The fossils were three million years old.

ANALYSIS: This is a bad argument. It’s possible that the ice melted. Or it’s possible that the fossils were from an animal that could live both on land and in the ocean (e.g. maybe some kind of bird.)

The fossils had only been found on the ocean floor, but that doesn’t mean they couldn’t be found anywhere else.

So while melting ice is a possible explanation, it isn’t the only explanation.

The main conclusion is that the available evidence is wrong and the ice sheet melted three million years ago. The last sentence supports the conclusion by showing how the fossils got to Antarctica.

___________

1. Close, but not quite. We don’t know how many people agree with the stimulus on this issue.
2. The stimulus disagrees with this answer choice. If this were true then the stimulus’ conclusion might not be true – this answer provides an alternate explanation for the discovery of the fossils.
3. CORRECT. The stimulus argues that the ice disappeared three million years ago, temporarily. 
4. This is just supporting evidence. It explains how the ice sheet could have melted. 
5. This sounds tempting but the argument wasn’t claiming that those were the only ways the ice sheet could have melted. The main point was that it did melt. We know it did because sea fossils were found.