GMAT Critical Reasoning (CR) | Re: Although exposure to asbestos is the primary cause for

Although exposure to asbestos is the primary cause of mesothelioma, a slow-developing cancer, researches 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. Reseaches hypothesize that this vaccine was the source of the virus found in mesotheliomas decades later.

POE is the
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