Some batches of polio vaccine used around 1960 were contaminated with

Question

Some batches of polio vaccine used around 1960 were contaminated with SV40, a virus that in monkeys causes various cancers. Some researchers now claim that this contamination caused some cases of a certain cancer in humans, mesothelioma. This claim is not undercut by the fact that a very careful survey made in the 1960s of people who had received the contaminated vaccine found no elevated incidence of any cancer, since __________.

(A) most cases of mesothelioma are caused by exposure to asbestos

(B) in some countries, there was no contamination of the vaccine

(C) SV40 is widely used in laboratories to produce cancers in animals

(D) mesotheliomas take several decades to develop

(E) mesothelioma was somewhat less common in 1960 than it is now

ID: 100808

GMATRockstar · Accepted Answer

https://www.youtube.com/watch?v=PfpR1KLidaA

KarishmaB · Answer

Responding to a pm:

"not undercut" means "not weakened".

Premises:
Some polio vaccines in 1960s were contaminated by SV40.
Researchers claim that SV40 can cause mesothelioma.

Question stem: This claim is not undercut by the fact that a very careful survey made in the 1960s of people who had received the contaminated vaccine found no elevated incidence of any cancer, since___________.

Normally, if one would say "a very careful survey made in the 1960s of people who had received the contaminated vaccine found no elevated incidence of any cancer", this would weaken the claim of the researchers. The researchers say that SV40 could cause mesothelioma but since no elevated incidence was found, we would doubt the claim of the researchers. 
But we need to find the reason this claim is not put in doubt by "no elevated incidence found".

Look at option (D): mesotheliomas take several decades to develop

The contaminated vaccine is given in 1960s. The survey was conducted in 1960s itself. If mesothelioma takes several decades to develop, we will not see an elevated incidence in the 60s decade itself. We will see an elevated incidence in later decades. Hence this option nicely completes the sentence.

All other options are irrelevant.

saurabhgoel · Answer

'D' for me.

Researchers are now at present making claim of the effect of something that happened in past .... so effect of contamination happened 1960 took time......

Survey was made in 1960,so this survey does not undercut the argument ("some researchers  now claim  that this contamination caused some cases of a certain cancer in humans, mesothelioma") because  mesotheliomas take several decades to develop

Archit143 · Answer

I was locked between C and D.
But eliminated C , as it presents the repackaged premise...Moreover we need to link that "why fewer people were found with the disease, but researcher claimed that there are people who suffer from cancer coz of the chemical"
D bridges the gap

Archit

kannu44 · Answer

Some researchers now claim that this contamination caused some cases of a certain cancer in humans, mesothelioma but in carfule survey done in 1960 there were no sign of cancer .
Probably it will take decade to develop

Hence D is the answer

adkikani · Answer

Hi Experts, 
Can you help me to distinguish if this is an assumption question or strengthen question? Furthermore, what does phrase - is not undercut - suggest?
I am presenting my analysis:
Some batches of polio vaccine used around 1960 were contaminated with SV40, a
virus that in monkeys causes various cancers.

This is a fact.

Some researchers now claim that
this contamination caused some cases of a certain cancer in humans,
mesothelioma.

This sentence is claim by researchers so it can be a belief of people other than author hence it is not main conclusion.

This claim is not undercut by the fact that a very careful survey
made in the 1960s of people who had received the contaminated vaccine found no
elevated incidence of any cancer, since ..

I took this whole sentence as fact and then I realized that only - This claim is not undercut by the fact - is the main conclusion. How can I avoid such traps? Further reading the argument also confused me since am i suppose to prove the fact that people in 1960 did not develop cancer in spite of getting contaminated vaccines. Since I wasn't able to understand argument in first place, I could not figure out correct OA.

GMATNinja · Answer

The claim of the researchers is that contamination of the polio vaccine used around 1960 caused some cases of mesothelioma in humans. "The fact that a very careful survey made in the 1960s of people who had received the contaminated vaccine found no elevated incidence of any cancer" could potentially weaken (ie "undercut") this claim. Why? Because this evidence seems to show that the contaminated vaccine did NOT cause the cases of mesothelioma, as stated in the researchers' claim.

Identifying the conclusion is, indeed, a crucial step in tackling questions like this: "{the researchers'} claim is not undercut by the fact that a very careful survey made in the 1960s of people who had received the contaminated vaccine found no elevated incidence of any cancer." Since that is the conclusion, the correct choice must answer the following question: why doesn't the survey evidence weaken the researchers' claim, even though the survey evidence  seems  to weaken the researchers' claim? If "mesotheliomas take several decades to develop", then patients surveyed soon after receiving the contaminated vaccine would not yet show signs of having the cancer, even if they do in fact have the cancer. In that case, the survey evidence does not undermine the researchers' claim, so (D) is correct.

mimishyu · Answer

Can someoneone help me with ( E )…??why its wrong??
If mesothelioma was less common in 1960 than it is now
then 1960 will indeed find no incidence of any cancer
 Later will find incidence of cancer….correspond to the passage
 how my logic is wrong..???

GMATNinja · Answer

Here's the precise wording of choice (E):

If mesothelioma were  somewhat less common  in 1960 than it is now, than we'd still expect mesothelioma to be present. Yet, the passage tells us that a very careful survey found  no elevated incident of any cancer .

The phrase "somewhat less common" does not indicate an extremely low rate of incidence, and it certainly doesn't indicate a total absence of this particular cancer. The difference in degree that's described by choice (E) doesn't line up with the difference of degree that's described in the passage.

That's why (E) can be eliminated. I hope this helps!

GMATWhizTeam · Answer

ANALYSIS of STIMULUS :
 
Given:
1. Virus SV40 causes cancer in monkeys
2. Some polio vaccine batches were contaminated in 1960.
3.  Claim of researchers  now  : Contaminated polio vaccine responsible for some cases of mesothelioma in humans.
4.  Fact that weakens the claim : A 1960 survey of people who took the contaminated vaccine that year shows no increase in any type of cancer occurrence in those people.
5.  Conclusion : despite the weakening fact, the claim is not to be devalued or dismissed, because__________
6.  We need to provide information to support the conclusion that the researchers claim is not to be devalued or dismissed
 
 PRE-THINKING 
1. Despite the fact that goes against the claim, the author believes the claim is not be taken at less value/undercut.This means there must be some reason for this belief
2.  Missing Link:  The survey was done in 1960, the very year the contaminated vaccine was given, but the claim is being made now that the contaminated vaccine caused mesothelioma.
3. What if when the survey was made, there was no evidence of increased evidence of any cancer/mesothelioma because mesothelioma does not develop at least within the first year or there are no immediately detectable signs of mesothelioma within the first year of humans being exposed to the factor causing mesothelioma? 
4. If that be the case, then despite the weakening fact, the claim would still hold value.
5.  Strengthener:  Mesothelioma does develop at least within a year of exposure of humans to the factor causing mesothelioma.

ANSWER CHOICE ELIMINATION 
(A) most cases of mesothelioma are caused by exposure to asbestos
(This choice weakens the researchers claim further by providing another cause behind the mesothelioma cases.
 Incorrect Choice )

(B) in some countries, there was no contamination of the vaccine
(This is no new information. We already know that “some” batches of the vaccine were contaminated. So, there might places where the vaccine was not contaminated. This choice presents a distorted version of the data already given in the passage.
 Incorrect Choice )

(C) SV40 is widely used in laboratories to produce cancers in animals
(Again, we already know that SV40 causes cancer in monkeys. This is totally irrelevant.
 Incorrect Choice )

(D) mesotheliomas take several decades to develop
(This is in line with our pre-thinking.
 Correct Choice )

(E) mesothelioma was somewhat less common in 1960 than it is now
(The issue at hand is not how common mesothelioma was in 1960 than it is now. In any case, the survey results found no evidence of mesothelioma in the people who took the contaminated vaccine. Whether mesothelioma existed in other people or was in general not very common is not the contention of the argument. Out of scope
 Incorrect Choice )

fauji · Answer

Option D!

This claim is not undercut by the fact that a very careful survey made in the 1960s of people who had received the contaminated vaccine found no elevated incidence of any cancer, since  mesotheliomas take several decades to develop . --   It accurately follows the sentence. We have "Since" in ending means some fact or strong data should be presented to take on the claim. option D does it effectively.

GMATRockstar · Answer

Anytime the word "since" precedes the blank in a "Complete the Passage" question-type, I think the best course of action is to treat it as an Assumption question, generally. This one is just a little harder with the whole "undercut" phrase. I go into this in more detail in my video explanation above!

xuloxulac · Answer

We should understand the meaning of "not undercut", which means "not weaken". Although the survey in 1960 shows that... (opposes the claim), but it "not undercut" = "not weaken" the mentioned claim

A_Nishith · Answer

The claim of the researchers is that contamination of the polio vaccine used around 1960 caused some cases of mesothelioma in humans. "The fact that a very careful survey made in the 1960s of people who had received the contaminated vaccine found no elevated incidence of any cancer" could potentially weaken (ie "undercut") this claim. Why? Because this evidence seems to show that the contaminated vaccine did NOT cause the cases of mesothelioma, as stated in the researchers' claim.

Identifying the conclusion is, indeed, a crucial step in tackling questions like this: "{the researchers'} claim is not undercut by the fact that a very careful survey made in the 1960s of people who had received the contaminated vaccine found no elevated incidence of any cancer." Since that is the conclusion, the correct choice must answer the following question: why doesn't the survey evidence weaken the researchers' claim, even though the survey evidence seems to weaken the researchers' claim? If "mesotheliomas take several decades to develop", then patients surveyed soon after receiving the contaminated vaccine would not yet show signs of having the cancer, even if they do in fact have the cancer. In that case, the survey evidence does not undermine the researchers' claim,

so (D) is correct.

Some batches of polio vaccine used around 1960 were contaminated with

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Critical Reasoning (CR) Questions

Some batches of polio vaccine used around 1960 were contaminated with

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards