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SV40--assumption!

Expert replies
by amysky_0205 » Tue Jan 15, 2013 6:56 pm
Although exposure to asbestos is the primary cause of mesothelioma, a slow-developing cancer, researchers believe that infection by the SV40 virus is a contributing cause, since in the United States 60 percent of tissue samples from mesotheliomas, but none from healthy tissue, contain SV40. SV40 is a monkey virus; however, in 1960 some polio vaccine was contaminated with the virus. Researchers hypothesize that this vaccine was the source of the virus found in mesotheliomas decades later.

Which of the following, if true, most strongly supports the researchers’ hypothesis?

A. SV40 is widely used as a research tool in cancer laboratories.
B. Changes in the technique of manufacturing the vaccine now prevent contamination with SV40.
C. Recently discovered samples of the vaccine dating from 1960 still show traced of the virus.
D. In a small percentage of cases of mesothelioma, there is no history of exposure to asbestos.
E. In Finland, where the polio vaccine was never contaminated, samples from mesotheliomas do not contain SV40.

OA: E

can someone explain this?
I have a little trouble choosing the right answer and don't know why it's right...
thank u!
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Source: — Critical Reasoning |

by pavan.paone » Wed Jan 16, 2013 5:44 am
clearly C
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by Bill@VeritasPrep » Wed Jan 16, 2013 1:29 pm
The hypothesis is that the vaccine was the source of the mesothelioma virus. The evidence provided is that 60% of mesothelioma samples, but no healthy samples, contain the virus. We also know that the virus contaminated a polio vaccine in 1960.

We are looking for a piece of evidence that would support the idea that the vaccine lead to the virus being present in the mesotheliomas.

A could actually weaken; it gives us an alternative explanation for how the virus could have ended up in the samples (cross-contamination in the lab)

B is irrelevant; we already know that contamination occurred.

C is also irrelevant; we already know that the vaccine contained the virus.

D can be ruled out because we're not concerned with asbestos causing mesothelioma. It's not part of the hypothesis.

E works; if it is truly the contaminated vaccine that led to the virus in the mesotheliomas, then you would not expect it to appear in cases where the contamination was not present.
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