GMAT CR Question

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GMAT CR Question

by sanjay12590 » Sat Aug 02, 2014 9:00 am
Hello Guys

Need your help with this CR Question.

It is well known that human tears often serve to moisten the eye, protect it from infection, and wash away irritants; such tears are called irritant or reflex tears. Dr. Field hypothesizes that emotional tears have a different biological function. She suggests that by shedding tears when under emotional stress people excrete harmful chemicals that build up in such body fluids as blood serum during emotional stress.

Each of the following, if true, provides some support for Dr. Field's hypothesis EXCEPT:

A)The people most likely to cry when undergoing emotional stress are less likely to suffer from stress-related diseases than is the population at large.

B)If a local anesthetic is applied to the surface of the eye, irritant and reflex tears are inhibited, but emotional tears are not.

C)The chemical composition of tears that are induced by grit in the eye is identical to the composition of tears induced by emotional stress.

D)The concentration of a substance that the body produces only under conditions of emotional stress is thirty times greater in tears than in blood serum.

E)Patients who suffer from a condition that prevents secretion of tears display a slower than normal physiological recovery from emotional stress

Please explain your answers.

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by David@GMATPrepNow » Mon Aug 04, 2014 9:03 am
Hi Sanjay,

To answer this Critical Reasoning question we need to identify which of the answer statements does NOT support Dr. Field's hypothesis. Our first step is to make sure that we understand what Dr. Field's hypothesis is. Here is my suggestion:

The human body has a special kind of tears that remove harmful chemicals caused by emotional stress.

We're looking for any answer statement that does NOT support this hypothesis - it could be anything that suggests that this kind of tear does not really exist; or that this kind of tear does something else in the body; etc. We have to ASSUME that each statement is TRUE, and assuming they are true, evaluate whether or not the statements support or do NOT support the hypothesis. Let's look at each answer:

A) The people most likely to cry when undergoing emotional stress are less likely to suffer from stress-related diseases than is the population at large. This answer supports the hypothesis. If tears remove the emotional stress that causes disease, and you cry when undergoing emotional stress, then you are going to have less emotional stress and therefore less disease. Because this statement supports the hypothesis, and we are looking for a statement that does NOT support the hypothesis, we can ELIMINATE A.

B) If a local anesthetic is applied to the surface of the eye, irritant and reflex tears are inhibited, but emotional tears are not.
This answer supports the hypothesis because it does not, NOT support it. I'm not trying to be cute in using a double negative. If we assume this statement to be true, then it does not undermine Dr. Field's hypothesis even if it does not really support it either. In fact, it is just information that does not, by itself, prove or disprove anything. We are told that people who are given the anesthetic still cry the special tears and eliminate the emotional stress-caused chemicals, and we can assume that her hypothesis cannot be refuted by this information. Eliminate B.

C) The chemical composition of tears that are induced by grit in the eye is identical to the composition of tears induced by emotional stress.
Wait! If this statement is true (and we have to assume that it is), then this totally undermines the hypothesis. If both kinds of tears are the same, then we can't say that one kind of tears does one thing, and the other kind of tears does something else. They're the same! If they are the same, they do the same thing. This statement does NOT support Dr. Field's hypothesis, so this is the answer we are after. C is the correct answer!

D) The concentration of a substance that the body produces only under conditions of emotional stress is thirty times greater in tears than in blood serum.
This statement supports the hypothesis. If the special tears eliminate the substance that is produced under emotional stress, then during times of emotional stress we would expect to find lots of it in the tears (because the body is trying to get rid of it). Eliminate D.

E) Patients who suffer from a condition that prevents secretion of tears display a slower than normal physiological recovery from emotional stress
This statement supports the hypothesis in the same way as suggested in answer D. If the special tears eliminate the substance that is produced under emotional stress, but the body cannot make them, then during times of emotional stress we would expect to find lots of it in the body (because the body cannot get rid of it), and therefore a more sick body that takes longer to get better. Eliminate E.

I hope this helps.