Logical reasoning PrepTest 156 · Section 2 · Question 16

This doesn't explain why smaller rats are more likely to suffer from heart problems. This answer choice just says smaller rats are likely to die from other diseases. Something is clearly wrong with smaller rats, but this answer choice doesn't explain what's wrong. If this answer choice demonstrated that these other fatal diseases might also lead to heart diseases, it would explain the surprising fact. But this answer choice doesn't do that.

Since this doesn't explain the correlation between size and heart problems in rats, we can mark it as a strong contender. We can take a quick glance at the remaining answer choices. If they all appear to explain why smaller rats are more likely to suffer from heart problems, we can select (A) and move on to the next question.

This explains why smaller rats are more likely to suffer from heart problems. If small rats' smaller blood vessels are more easily clogged with fatty deposits, this would explain why they're more easily prone to heart problems. We have to rely on a widely-held assumption that clogged blood vessels will lead to heart problems, but such assumptions are generally OK on Logical Reasoning, especially Paradox questions.

This explains why smaller rats are more likely to suffer from heart problems. If small rats live more stressful lives, this would explain why they're more easily prone to heart problems. We have to rely on a widely-held assumption that stress can lead to health problems, but such assumptions are generally OK on Logical Reasoning, especially Paradox questions.

This explains why smaller rats are more likely to suffer from heart problems. If malnutrition can cause rats to be both small and have weak hearts, it makes sense that small rats tend to be more prone to heart problems. We have to rely on a widely-held assumption that a weak heart would contribute to heart problems, but such assumptions are generally OK on Logical Reasoning, especially Paradox questions.

This explains why smaller rats are more likely to suffer from heart problems. If larger rats and average-sized rats have better cardiovascular conditioning, it would make sense that smaller rats are more likely to suffer from heart problems. We have to rely on a widely-held assumption that poor cardiovascular conditioning could contribute to heart problems, but such assumptions are generally OK on Logical Reasoning, especially Paradox questions.

Some test-takers are tempted by (E), which is understandable. Admittedly, this answer choice doesn't explain why larger rats are less prone to heart problems than average-sized rats. However, between (A) and (E), (E) at least explains why small rats are more likely to suffer from heart disease. (A) doesn't explain why large rats are less likely or why small rats are more likely to suffer from heart problems. So, we'll have to eliminate (E) and select (A).