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

IMO it is D.

Conclusion is "galanin causes rats to crave fatty foods" and those rats chose to eat fatty food over lean food.

a) The craving for fatty foods does not invariably rsult in a rats chosing those foods over lean foods.
>> weakens the argument.
b) The brains of the rats that consistently chose to eat fatty foods did not contain significantly more fat than did thebrains of rats that consustently choos elean foods.
>> Content of fat in brain is of no use for conclusion.
c) The chemical components are present in both fatty and lean foods
>> Not relevant for conclusion
d) The rats that preferred fatty foods had the higher concentrations of galanin in their brains before they were offered fatty foods.
>> Yes. If this statement is correct, then we can safely concluse that galanin causes rats to crave fatty foods and so they eat the fatty food.
e) rats that metabolize fat less efficiently than do other rats develop high concentrations of galanin in their brains.
>> Rat's metabolism has no place in conclusion.

Thanks mads. Much appreciated.

fyi
That was a question from PowerScore CR Bible

Doesnt the option A says that "craving" doesnt lead the rat to choose fatty food ?
I felt here the alternate opinion is eliminated. Craving doesnt lead rat to choose fatty foods but its the galanin which is responsible to choose fatty food. I didnot understand the phrase "doesnot invariably"

Please help.

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?

a) The craving for fatty foods does not invariably rsult in a rats chosing 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 thebrains of rats that consustently choos elean foods.
c) The chemical components are present in both fatty 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.


Point A B and C does not necesarily support the argument but choice D clearly mentions that the mice already had galanin before eating fatty food and fatty food did not cause the deposition of galanin in them so Point D supports the argument. while Point E talks about metabolism which is out of scope.

So Answer is D.

Further to this, may we say that:-
Conclusion: Protein galanin in brain causes rats to crave (remember the word crave and not choose) fatty foods.
A says that craving for fatty foods does not necessarily result in rat's choosing (and not craving) those foods over lean foods.

This way, the option A does not make any sense at all. Conclusion talks about craving but A talks about choosing. So, A can be eliminated on this ground.

We need to Strengthen the Argument. The conclusion says that galanin (G) causes rats to eat more fatty foods (FF).

a) The craving for fatty foods does not invariably result in a rats choosing those foods over lean foods.

Incorrect. This option says that craving for fatty foods not always results in rats choosing fatty foods. So, there might be some other reasons than G. Also, this option does not really touch G.

b) The brains of the rats that consistently chose to eat fatty foods did not contain significantly more fat than did thebrains of rats that consustently choos elean foods.

Incorrect. Galanin is not mentioned here at all.

c) The chemical components are present in both fatty and lean foods

Incorrect. We are not concerned with chemical components. This statement is irrelevant.

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

Correct. Okay, this option says that galanin made the rats prefer fatty foods. This is what we are looking for.

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

Incorrect. We are not concerned with how rats metabolize fat. So, efficiency is irrelevant.

The argument talks about a Cause-->effect relation.
Cause=galanin
effect=rats crave fatty foods

So the argument is based on the assumption that fatty foods do not cause an higher level of gelatin i the brain.

A Strengthener could be: " rats with low level of gelatin after eating fatty foods did not report an increase level of gelatin"

Among all the options Option D is quite in line with our strengthener and hence it is correct

Cause ---> Effect
Higher ... galanin --->Cave fatty foods
Why can't the fatty food lead to higher concentrations of galanin?
D) The rats that preferred fatty foods had higher concentrations of galanin in their brains before they were offered fatty foods.
This answer eliminates the possibility that the stated causal relationship is reversed.

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.

cause and effect: Hi concentration of G -------> craving for fatty foods
why?
rats who chose fatty foods had higher concentration of G than those who chose lean

in order to strengthen we need to look for an answer that :

1. removes all alternate causes
2. show that craving of fatty foods ONLY occurs when the concnetration of G is higher than other rats
3. that there is no reversal.....ie....the effect is not causing the cause

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

a) The craving for fatty foods does not invariably rsult in a rats chosing those foods over lean foods.

this means if there is a craving for fatty foods (ff) the rats choose either.....with no pref.
so is this saying that ONCE you crave ff, there is no pref either way? if yes....therefore it does NOT address what is causing the craving.

b) The brains of the rats that consistently chose to eat fatty foods did not contain significantly more fat than did thebrains of rats that consustently choos elean foods.

concentrations of fats is not under discussion. more or less fat is not part of the CE relationship

c) The chemical components are present in both fatty and lean foods

vague

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

this strengthens the CE.......so is correct
since they already had hi concentration of G they chose ff
Effect is ONLY due to the CAUSE


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

this presents another CE: low fat metabloism ---------> hi conc of G
so out of scope

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