LSAT Explanation PT 33, S3, Q20: Galanin is a protein found in

LSAT Question Stem

Which one of the following, if true, most supports the argument? 

Logical Reasoning Question Type

This is a Strengthen question. 

Correct Answer

The correct answer to this question is D. 

LSAT Question Complete Explanation

First, let's summarize and analyze the argument in the passage. The argument is structured as follows:

Premise 1: Rats that consistently chose fatty foods had higher concentrations of galanin in their brains.

Premise 2: Rats that consistently chose lean foods had lower concentrations of galanin in their brains.

Conclusion: Galanin causes rats to crave fatty foods.

The passage presents a causal relationship between galanin and the craving for fatty foods in rats. To better understand this, let's use a simple example: Imagine there are two groups of people - one group that loves chocolate and another group that doesn't. Researchers find that the chocolate lovers have a higher concentration of a certain protein in their brains than the non-chocolate lovers. The researchers then conclude that this protein causes people to love chocolate.

An "Evaluate" question for this argument could be: "Did the rats have higher concentrations of galanin in their brains before they started consuming fatty foods?"

Now, let's discuss the answer choices for the Strengthen question, which asks us to find the statement that most supports the argument.

a) If the craving for fatty foods doesn't always result in choosing those foods, it doesn't necessarily strengthen the argument, as it doesn't provide any additional evidence for the causal relationship between galanin and craving fatty foods.

b) The fat content in the brains of rats is not relevant to the argument, as the argument is focused on the concentration of galanin and its relationship with craving fatty foods. This answer choice doesn't strengthen the argument.

c) The presence of galanin's chemical components in both fatty and lean foods doesn't help the argument, as it doesn't provide any additional evidence for the causal relationship between galanin and craving fatty foods. In fact, it may even hurt the argument.

d) This answer choice strengthens the argument by eliminating the possibility that the causal relationship is reversed. If the rats had higher concentrations of galanin before eating fatty foods, then it's more likely that galanin causes the craving for fatty foods, rather than fatty foods causing higher concentrations of galanin.

e) This answer choice suggests that the causal relationship in the conclusion might be reversed, which would weaken the argument. It implies that rats with less efficient fat metabolism develop high concentrations of galanin, rather than galanin causing the craving for fatty foods.

In conclusion, the correct answer choice is (D), as it strengthens the argument by eliminating the possibility of a reversed causal relationship and making it more likely that galanin causes rats to crave fatty foods.