LSAT 106 | Section 3 | Logical Reasoning: Q25

LR Question 25 Explanation

QUESTION TEXT: The interstitial nucleus, a subregion of the brain’s…

QUESTION TYPE: Weaken

CONCLUSION: The size of male cats’ interstitial nuclei determines whether they can catch disease X.

REASONING: The interstitial nucleus is part of the hypothalamus. Male cats with disease X were autopsied. They had larger than usual interstitial nuclei.

ANALYSIS: There’s a lot of fluff in this stimulus. I cut out the description of female cats, because they don’t relate to the argument.

Female cats are only given to add context. But if you took out all the information about female cats, the argument would stay exactly the same. Try it. Replace “as large as…female cats” with “larger”.

___________

1. The conclusion was only about whether male cats will catch disease X. Female cats don’t matter.
2. This is like saying: “many humans who have cancer also catch colds.”
    
   Other diseases aren’t necessarily important; only disease X matters.
3. This slightly strengthens the argument, by showing that large female interstitial nuclei are also correlated with disease X.
4. It’s to be expected that there will be variation around an average. Some humans are taller than average and some humans are shorter than average, for example.
    
   The size of the interstitial nuclei was significant because every male cat with disease X had a large interstitial nucleus.
5. CORRECT. This is very tricky. The interstitial nucleus is part of the hypothalamus. And disease X is part of disease Y.
    
   So if there’s no evidence of a relation between the hypothalamus and disease Y, then there must be no evidence of a relation between the interstitial nucleus (part of the hypothalamus) and disease X (part of disease Y).