A study of the dietary habits of a group of people who had recently d

Question

A study of the dietary habits of a group of people who had recently developed cancer and a group without cancer found that during the previous five years the diets of"
"the two groups' members closely matched each other in the amount of yogurt they contained. Yogurt contains galactose, which is processed in the body by an enzyme. In the people with cancer the levels of this enzyme were too low to process the galactose in the yogurt they were consuming. It can be concluded that galactose in amounts exceeding the body's ability to process it is carcinogenic.

Of the following, which one constitutes the strongest objection to the reasoning in the argument?

(A) The argument fails to consider whether the dietary habits of everyone in the two groups were the same in all other respects."
(B) The argument neglects to recommend that people with low levels of the enzyme avoid eating yogurt."
(C) The argument focuses on only one substance that can increase the risk of cancer when it is well known that there are many such substances."
(D) The argument overlooks the possibility that cancer causes low levels of the enzyme."
(E) The argument does not specify whether any member of either group lacked the enzyme entirely.

LSAT 69

AshutoshB · Answer

A. This sounds tempting, but it’s not necessary. Read carefully. It asks whether:
1. Everyone’s diet
2. was exactly the same
3. in all other respects No medical study meets this standard. It’s impossible. People’s diets are very different. A study can still tell us something, even if not every variable is controlled with perfect accuracy.

B The argument is just making a claim about galactose. It doesn’t have to make practical recommendations to improve people’s lives.

C The argument doesn’t have to describe every possible cause of cancer. There are thousands of causes. The argument didn’t say that galactose is the only cause of cancer.

D CORRECT.  If cancer causes low enzyme levels, then galactose malabsorption is an effect of cancer, not a cause.

E The groups were presumably somewhat large. If one person in a group lacked the enzyme, that shouldn’t affect the overall study.

brianmontanaweb · Answer

Since we're looking for the reasoning we want to break down the argument. We can identify the study comparing two groups of people with similar diets, those with cancer and those without. The conclusion states that people who can not process galactose leads to it being carcinogenic. Since the study compares groups with cancer and without cancer we can attack this portion of the argument.

A, and B are already addressed by stating "closely matched each other in the amount of yogurt they contained", and diet is the issue in the study.

C is out of scope, there are many variables that could impact the study but that's not the focus of the argument.

E there was a correlation between those with levels lower and higher, which is cancer and no cancer. Incorrect.

D is correct since it addresses the concern between those with and those without cancer could lead to a difference in the enzyme levels.

Suruchim12 · Answer

Hi Experts /  GMATNinja  /  Bunuel

Can someone please help me understand why A should be eliminated?

It came down to A and D for me and I chose A cuz as I understand it:

The conclusion is: Galactose causes cancer. Basis the premise that people with cancer were known to have low levels of an enzyme that processes Galactose as compared to the group with no cancer. 
Assumption is that : There is no other cause of the cancer in the group

AND therefore isnt that the strongest objection we can make?

GMATNinja · Answer

The author tells us that "in the people with cancer," the levels of a certain enzyme were "too low to process the galactose in the yogurt they were consuming." Based on this fact, the argument concludes that "galactose in amounts exceeding the body's ability to process it is carcinogenic." But is that the only way to interpret the evidence?

We know that people with cancer had lower amounts of the enzyme that processes galactose. In other words, we know that lower amounts of this enzyme are  correlated  with cancer. So it's definitely possible that excess galactose is what's causing the cancer. But it's also possible that the cancer itself is causing lower levels of the enzyme.

Let's now consider (D):

This would suggest an alternative explanation for the evidence. The author thinks that low enzyme levels led to a build up of galactose that caused cancer. But we only know that low enzyme levels and cancer are  correlated , not that one  causes  the other. In fact, it's also possible that cancer caused the low enzyme levels, and not the other way around. This alternative explanation of the evidence would provide a strong objection to the reasoning.

So because (D) provides a strong objection, it's correct.

Let's now consider (A):

We are trying to provide an objection to the reasoning in the argument. The reasoning suggests that because the people with cancer had less of a certain enzyme, this caused them to have excess galactose, which in turn caused the cancer.

Notice that the above reasoning doesn't require the two groups to have diets that are "the  same  in all other respects." Just because their diets differed in some way wouldn't constitute a strong objection to the argument. They'd need to differ in some way that would be potentially carcinogenic. Since (A) doesn't indicate whether that's the case, it's not a strong objection.

From another angle: it's definitely possible that some factor aside from enzyme levels contributed to the development of cancer, but this wouldn't directly damage the reasoning in the argument. In other words, just because there was some other carcinogen in the diets of the two groups, doesn't mean that excess galactose wasn't also carcinogenic.

For both of those reasons, (A) isn't the strongest objection to the argument, and it's incorrect.

I hope that helps!

unraveled · Answer

A study of the dietary habits of a group of people who had recently developed cancer and a group without cancer found that during the previous five years the diets of" "the two groups' members closely matched each other in the amount of yogurt they contained. Yogurt contains galactose, which is processed in the body by an enzyme. In the people with cancer the levels of this enzyme were too low to process the galactose in the yogurt they were consuming. It can be concluded that galactose in amounts exceeding the body's ability to process it is carcinogenic.

Of the following, which one constitutes the strongest objection to the reasoning in the argument?

(A) The argument fails to consider whether the dietary habits of everyone in the two groups were the  same in all other respects ." - WRONG. Irrelevant. Whatever is mentioned we need to find objection in that.
(B) The argument  neglects to recommend  that people with low levels of the enzyme avoid eating yogurt." - WRONG. Like A scope shift is there.
(C) The argument focuses on only one substance that can increase the risk of cancer when it is well known that  there are many such substances ." - WRONG. True that there might be but that's again irrelevant. This could have been an answer had D been not there or was formulated in such a way that it would have been wrong. 
(D) The argument overlooks the possibility that cancer causes low levels of the enzyme." - CORRECT. After cancer the enzyme level decreases. This possibility is ignored. 
(E) The argument does not specify whether any member of either group  lacked the enzyme entirely . - WRONG. Again a kind of distraction.

Answer D.

VerbalBot · Answer

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A study of the dietary habits of a group of people who had recently d

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