Neuroscientists are making progress in discovering more about the caus

Question

Neuroscientists are making progress in discovering more about the cause of Alzheimer’s disease. Alzheimer’s disease patients suffer from dementia and sever memory loss. Autopsies performed on such patients have revealed the presence of brain lesions caused by abnormal protein deposits. Similar deposits are also found in the brains of elderly patients who do not suffer from Alzheimer’s disease. It follows that everyone who lives long enough will eventually develop Alzheimer’s disease.

Which one of the following statements, if true, most seriously undermines the conclusion that everyone who lives long enough will eventually develop Alzheimer’s disease?

(A) The lesions found in the brains of non-Alzheimer’s disease patients are far less extensive than those found in the brains of Alzheimer’s disease patients.

(B) The developing brain produces a greater number of cells than it will ever use. The extra cells are later destroyed by what biologists call “programmed cell death.”

(C) The procedure that allows scientists to discover the presence of protein deposits during an autopsy is not yet refined enough to ensure detection of the lesions in all patients.

(D) Autopsies have shown that some people lack the chemical necessary for protein deposits to cause brain lesions.

(E) Though most Alzheimer’s disease patients develop the disease when they are in their late fifties to early seventies, the frequency of patients who develop the disease in their forties is on the rise.

EncounterGMAT · Answer

Cause & Effect argument.  
P: Neuroscientists-discovering more about the cause of Alzheimer’s disease.
P:Alzheimer’s disease patients suffer from dementia and sever memory loss.
P:Autopsies-presence of brain lesions caused by abnormal protein deposits-similar deposits found in the brains of elderly patients who do not suffer from Alzheimer’s disease. 
C:long live-develop Alzheimer’s disease.

WEAKEN

(A) The lesions found in the brains of non-Alzheimer’s disease patients are far less extensive than those found in the brains of Alzheimer’s disease patients.
INCORRECT. pretty much strengthens the argument.

(B) The developing brain produces a greater number of cells than it will ever use. The extra cells are later destroyed by what biologists call “programmed cell death.”
INCORRECT. Out of scope. Nothing as such is even mentioned in the passage. Unnecessary information.

(C) The procedure that allows scientists to discover the presence of protein deposits during an autopsy is not yet refined enough to ensure detection of the lesions in all patients.
INCORRECT. the procedure was done on dead people, who suffered from alzheimer's and old people because of similarity of lesions in them. If procedure was so easy and accurate, everyone could have found whether they suffer of is going to suffer from alzheimer's.

(D) Autopsies have shown that some people lack the chemical necessary for protein deposits to cause brain lesions.
 CORRECT.  some people(old/young-anyone) lack chemical for protein deposits to cause brain lesions, not all will suffer from alzheimer's.

(E) Though most Alzheimer’s disease patients develop the disease when they are in their late fifties to early seventies, the frequency of patients who develop the disease in their forties is on the rise.
INCORRECT. definition of old is not given in the question. so can't say comes in young/old category.

auradediligodo · Answer

Neuroscientists are making progress in discovering more about the cause of Alzheimer’s disease. Alzheimer’s disease patients suffer from dementia and sever memory loss. Autopsies performed on such patients have revealed the presence of brain lesions caused by abnormal protein deposits. Similar deposits are also found in the brains of elderly patients who do not suffer from Alzheimer’s disease. It follows that everyone who lives long enough will eventually develop Alzheimer’s disease.

Which one of the following statements, if true, most seriously undermines the conclusion that everyone who lives long enough will eventually develop Alzheimer’s disease?

Weaken question

Pre-thinking

Look carefully at the conclusion: It claims that  Everyone  will develop Alzheimer's disease since protein deposits are found also in elderlies.

Now   Option D   claims that some people will not develop lesions since they lack of the chemical needed for the lesions to occur. Hence not everyone will have the disease and the argument is weakened

(A) The lesions found in the brains of non-Alzheimer’s disease patients are far less extensive than those found in the brains of Alzheimer’s disease patients.

(B) The developing brain produces a greater number of cells than it will ever use. The extra cells are later destroyed by what biologists call “programmed cell death.”

(C) The procedure that allows scientists to discover the presence of protein deposits during an autopsy is not yet refined enough to ensure detection of the lesions in all patients.

(D)    Autopsies have shown that some people lack the chemical necessary for protein deposits to cause brain lesions.

(E) Though most Alzheimer’s disease patients develop the disease when they are in their late fifties to early seventies, the frequency of patients who develop the disease in their forties is on the rise.

analytica233 · Answer

(C) The procedure that allows scientists to discover the presence of protein deposits during an autopsy is not yet refined enough to ensure detection of the lesions in all patients.
(C) is incorrect because if the procedures does NOT ensure detection of the lesions in ALL patients, it can ensure detection of the lesions of 99.99% patients. This does not weaken the conclusion. The conclusion is based on the study of a SAMPLE of patients.

KaranB1 · Answer

GMATNinja   ChiranjeevSingh 
I'm unable to understand how come D is a better answer choice than A.

Kindly share your two cents.

hero_with_1000_faces · Answer

EXPERT .

I was torn between C and D. both seemed right to me.

(D) Autopsies have shown that some people lack the chemical necessary for protein deposits to cause brain lesions.
This is right, no doubt.

However,

(C) The procedure that allows scientists to discover the presence of protein deposits during an autopsy is not yet refined enough to ensure detection of the lesions in all patients.

If the Elderly patients had brian lesions, which were undetected and they no dementia, then it means "Brian Lesions" do not cause Alzhemier and hence everyone will not get dementia based on the reasoning of argument.

Can someone help me with C

ravigupta2912 · Answer

This is a typical logical gap based question. Lets understand.

Premises 
Protein deposits are found in both groups (suffer from alzheimer and those who don't).
Elderly with alzheimer have lesions in brain caused due to protein deposits as revealed by autopsy
 Conclusion 
Eventually everyone will get Alzheimers. The assumption or the logical gap is that brain lesions lead to alzheimer and eventually the protein deposits will cause those leading everyone to get alzheimers.

Now, to undermine the above conclusion, we need a statement which undermines this logical gap or assumption. D does that perfectly as it breaks the chain between protein deposits causing brain lesions (and hence alzheimers). Winner here.

B, C and E are completely irrelevant and are easy eliminations. A is a strengthener and similar info provided can cause a trap answer.

Yellkrishna · Answer

The argument concludes that people who live long enough will develop Alzheimer’s because they develop protein deposits in the brain.

A. It says the lesions are far less extensive. That does not mean that they don’t exist or won’t develop as people age. 
B. Irrelevant 
C. The procedure is not refined, so people who have lesions might not have the deposits detected by the procedures. If anything, it strengthens. 
D. Some people lack the chemical to develop protein deposits, so lesions might not develop, so Alzheimer's might not develop. So this weakens the argument. 
E. This does not address the issue about the people who live long enough developing Alzheimer's. 
Hence D.

Posted from my mobile device

gmat108 · Answer

Autopsies have shown that some people lack the chemical necessary for protein deposits to cause brain lesions.
 Since we don't know whether these autopsies are from people who have lived long enough, these some people might be teens or kids. 
We have no evidence that proves, these are the autopsies report from the relevant age group.

Jeemate · Answer

The main contenders for this question are A & D:
Option A: Some have less lesion than others. This information doesn't weaken the conclusion that "everyone" will eventually suffer from the disease.
 Option D:  Some people lack the chemical needed to form those lesions. This info. attacks the conclusion that "everyone" will suffer from the disease.

Oppenheimer1945 · Answer

KarishmaB , How are we eliminating C here.

Option D talks about "some" people. Is this really a weakener?

KarishmaB · Answer

Premises:

Alzh patients have brain lesions caused by abnormal protein deposits.
Such abnormal protein deposits are also found in elderly people without Alzh.

Conclusion: Everyone who lives long enough will eventually develop Alzheimer’s disease.

Looks like with age, abnormal protein deposits are created in everyone. With time, they lead to brain lesions and hence Alzheimer's. So anyone who lives long enough will get Alzheimer's.

What will weaken this?

(A) The lesions found in the brains of non-Alzheimer’s disease patients are far less extensive than those found in the brains of Alzheimer’s disease patients.
 
Does not weaken that they will get Alzh. The lesions are far less extensive for now. Had they lived long enough, the lesions would have likely become extensive enough to develop Alzh.

(B) The developing brain produces a greater number of cells than it will ever use. The extra cells are later destroyed by what biologists call “programmed cell death.”

No connection to our current argument.

(C) The procedure that allows scientists to discover the presence of protein deposits during an autopsy is not yet refined enough to ensure detection of the lesions in all patients.

This tells us that it is possible that people with protein deposits had lesions but they could not be detected. If anything, it points us again in the direction of the conclusion only. We know that protein deposits were found in elderly patients (with or without Alzh). Did they actually have brain lesions yet or not doesn't matter. Our current tech says that there are no brain lesions. But if our current tech is not sensitive enough to detect brain lesions, then it is possible that the brain lesions have already started developing though we can't see them yet. The conclusion is that with time, the deposits will lead to brain lesions. 
Hence our conclusion is not weakened.

(D) Autopsies have shown that some people lack the chemical necessary for protein deposits to cause brain lesions.
 
The conclusion specifically says "ALL who live long enough will develop Alzh". If we can prove it wrong even in 1 case, it weakens our conclusion. 
If for some people, the protein deposits will not lead to brain lesions, then we cannot say that all will develop Alzh. Hence, it weakens our conclusion.

(E) Though most Alzheimer’s disease patients develop the disease when they are in their late fifties to early seventies, the frequency of patients who develop the disease in their forties is on the rise.

Alzh is hitting in early years too now. Doesn't weaken our conclusion.

Answer (D)

Contropositive · Answer

Hi  KarishmaB

I need little help with this option.
Argument never establishes that Lesions cause Alzheimer. Argument merely talks about the correlation between lesions and Alzheimer. 
So, doen't this option takes for granted that lesions cause Alzheimer?
Maybe, it is the protein deposits, which are eventually causing Alzheimer, and lesions are merely side products.

Pranavsawant · Answer

I don't really agree with D being the right answer. D states that "Autopsies have shown that some people lack the chemical necessary for protein deposits to cause brain lesions." 
But this never says that the people lacking that chemical will live long enough. The arguments says that people who live long enough will get the disease. What if all people that lack this chemical never live long enough? Then this doesn't weaken the conclusion at all! Some people can't have those brain lesions, okay but then how are we to know that these people will live long enough as well? The argument is hinging upon longevity.

I have more reason to believe that A is the answer (although not waterproof). A says "The lesions found in the brains of non-Alzheimer???s disease patients are far less extensive than those found in the brains of Alzheimer???s disease patients." 
So it could be that these less extensive lesions don't result in Alzheimers. The passage says that right now people do exist with these lesions and without Alzheimers. So the lesions being less extensive does give me reason to believe that they won't get the disease.

D has a very clear hole: How do we know that those ppl that lack the chemical live long enough? Unless we prove that, D is such a weak answer

Neuroscientists are making progress in discovering more about the caus

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