Galanin is a protein found in the brain. In an experiment, rats that

Question

Galanin is a protein found in the brain. In an experiment, rats that consistently chose to eat fatty foods when offered a choice between lean and fatty foods were found to have significantly higher concentrations of galanin in their brains than did rats that consistently chose lean over fatty foods. These facts strongly support the conclusion that galanin causes rats to crave fatty foods.

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

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

A. The craving for fatty foods does not invariably result in a rat’s choosing those foods over lean foods.

B. The brains of the rats that consistently chose to eat fatty foods did not contain significantly more fat than did the brains of rats that consistently chose lean foods.

C. The chemical components of galanin are present in both fatty foods and lean foods.

D. The rats that preferred fatty foods had the higher concentrations of galanin in their brains before they were offered fatty foods.

E. Rats that metabolize fat less efficiently than do other rats develop high concentrations of galanin in their brains.

Aswin12 · Answer

Option D  is the correct answer.

This is a strengthener question and we have to choose an option that strengthens the conclusion which states Galanin causes the craving for fatty foods and option D says that Galanin was high in rats that chose fatty food even before they were offered the food. 
So it proves that the cause and effect relation is correct cause otherwise there is a chance consumption of fatty food caused the amount of galanin in the rats brain to increase and this is not the case

Bunuel · Answer

OFFICIAL EXPLANATION This stimulus also contains causal reasoning—the conclusion takes a correlation and turns it into a causal relationship: https://gmatclub.com/forum/download/file.php?id=61086 As with all causal arguments, once you identify the causality, you must immediately look to the question stem and then attack. In this instance, the author simply assumes that galanin is the cause. Why can’t the fatty foods lead to higher concentrations of galanin? Answer choice (A): If anything, this answer choice may hurt the argument by showing that the cravings do not always lead to choosing fatty foods. But, since the author uses the phrase “consistently chose” to describe the choices of the rats, an answer stating that rats did not “invariably” choose fatty foods has no effect on the argument. Answer choice (B): This is a Shell Game answer because the test makers try to get you to fall for an answer that addresses the wrong issue. The argument discusses the concentration of galanin in the brains of rats; no mention is made of the fat content of the brains of rats. This answer, which focuses on the fat content in the brains of rats, therefore offers no support to the argument. Even though the brain might not contain more fat, a rat could still consistently choose and eat foods with a higher fat content. Answer choice (C): The argument is that galanin in the brain causes rats to crave fatty foods. The fact that galanin is in the food does not help that assertion and may actually hurt the argument. Answer choice (D): This is the correct answer. The answer strengthens the argument by eliminating the possibility that the stated causal relationship is reversed: if the rats had higher concentrations of galanin prior to eating the fatty foods, then the fatty foods cannot be the cause of the higher concentration of galanin. As discussed earlier in the chapter, this approach strengthens the argument by making it more likely that the author had the original relationship correct. Answer choice (E): This answer choice hurts the argument by suggesting that the causal relationship in the conclusion is reversed. Remember that in Strengthen questions you can expect to see Opposite answers, and this is one. 2021-03-29_03-25-19.png

agrasan · Answer

Hi experts  KarishmaB   MartyMurray   DmitryFarberMPrep

B. The brains of the rats that consistently chose to eat fatty foods did not contain significantly more fat than did the brains of rats that consistently chose lean foods.

Is (B) wrong because we simply don't know what is the effect of higher fats on craving? In other words, neither (B) nor the argument has a  causation link  between fats and craving for fatty foods.

Please let me know if something is wrong with my reasoning.

guddo · Answer

Galanin is a protein found in the brain. In an experiment, rats that consistently chose to eat fatty foods when offered a choice between lean and fatty foods were found to have significantly higher concentrations of galanin in their brains than did rats that consistently chose lean over fatty foods. These facts strongly support the conclusion that galanin causes rats to crave fatty foods.

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

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

Rats that choose fatty foods have more galanin, and the argument claims galanin is the cause. The best support shows the high galanin came first (cause) rather than being a result of eating fat or something else.
 
(A) The craving for fatty foods does not invariably result in a rat’s choosing those foods over lean foods.

This weakens the link between “craving” and “choice,” so it does not support the causal claim.

(B) The brains of the rats that consistently chose to eat fatty foods did not contain significantly more fat than did the brains of rats that consistently chose lean foods.

This slightly rules out “more brain fat” as an explanation, but it does not address the key issue of whether galanin is the cause or the effect.

(C) The chemical components of galanin are present in both fatty foods and lean foods.

Irrelevant. That does not show whether brain galanin drives cravings.

(D) The rats that preferred fatty foods had the higher concentrations of galanin in their brains before they were offered fatty foods.

This is the strongest support. It shows the galanin difference existed  before  the diet choice, which makes it much more likely galanin is causing the preference rather than fatty eating increasing galanin.  This best supports the causal claim.

(E) Rats that metabolize fat less efficiently than do other rats develop high concentrations of galanin in their brains.

This suggests a third factor (fat metabolism) could be driving galanin levels, which would weaken the claim that galanin itself is the cause of craving.

Answer: (D)

guddo · Answer

I think, your reasoning is basically right.

(B) is weak because it only rules out one specific alternative story: “they ate fatty food, so their brains got fattier, and that fattier brain (not galanin) explains the preference.” But the argument never established that brain fat would affect craving, so eliminating it is only a minor help.

It also does nothing to address the main causality gap:  which came first , high galanin or fatty eating. That’s why D is much stronger.

ParamjitDasGMAT · Answer

Hi  agrasan ,

In addition to the elaborate explanation by  guddo , do note that this type of an answer choice shows up quite frequently in causation-correlation-based questions (i.e., that  Y didn't cause X / occur before X ).

Another reason (B) cannot be the assumption is that  an assumption  means   what I, as an author, subconsciously took to be true while going from the premise(s) to the conclusion.

Trust me, once you approach assumption questions this way, your accuracy will shoot up. The negation strategy can, of course, help in certain situations, but more often than not, it should be used only for verification rather than as a selection tool. If thought of in the above manner, you will realize why (B) wouldn't be an assumption.

Hope this helps.

Hope this helps.

Galanin is a protein found in the brain. In an experiment, rats that

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Galanin is a protein found in the brain. In an experiment, rats that

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