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Although genetic mutations in bacteria and viruses can lead to... Q17 GMAT OG Verbal


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Although genetic mutations in bacteria and viruses can lead to epidemics, some epidemics are caused by bacteria and viruses that have undergone no significant genetic change. In analyzing the latter, scientists have discovered the importance of social and ecological factors to epidemics. Poliomyelitis, for example, emerged as an epidemic in the United States in the twentieth century; by then, modern sanitation was able to delay exposure to polio until adolescence or adulthood, at which time polio infection produced paralysis. Previously, infection had occurred during infancy, when it typically provided lifelong immunity without paralysis. Thus, the hygiene that helped prevent typhoid epidemics indirectly fostered a paralytic polio epidemic. Another example is Lyme disease, which is caused by bacteria that are transmitted by deer ticks. It occurred only sporadically during the late nineteenth century but has recently become prevalent in parts of the United States, largely due to an increase in the deer population that occurred simultaneously with the growth of the suburbs and increased outdoor recreational activities in the deer's habitat. Similarly, an outbreak of dengue hemorrhagic fever became an epidemic in Asia in the 1950's because of ecological changes that caused Aedes aegypti, the mosquito that transmits the dengue virus, to proliferate. The stage is now set in the United States for a dengue epidemic because of the inadvertent introduction and wide dissemination of another mosquito, Aedes albopictus.

 

6. Which of the following, if true, would most strengthen the author's assertion about the cause of the Lyme disease outbreak in the United States?

(A) The deer population was smaller in the late nineteenth century than in the mid-twentieth century.

(B) Interest in outdoor recreation began to grow in the late nineteenth century.

© In recent years the suburbs have stopped growing.

(D) Outdoor recreation enthusiasts routinely take measures to protect themselves against Lyme disease.

(E) Scientists have not yet developed a vaccine that can prevent Lyme disease.

 

 

OA: A.

 

Can anyone suggest why A is correct. OG says, "If the deer population was smaller when the disease occurred only sporadically, then the author's claim that the mid-century rise in deer population is one of the causes of Lyme disease is strengthened."

 

However, according to me, the higher deer population in "Mid-twentieth century" makes the option confusing because the author mentions about recent prevalence of the disease, and nothing about Mid-20th century" in the passage.

What I am trying to say is that

"recent" does not equal to "mid-twentieth century"

Said that..The option, then, implies that deer population was small in late 19th century, higher in mid-20th century and recently on an increase.

Which makes it a contradiction to the fact that the disease sporadically occurred in late 19th and then recently became prevalent again..

The option implies to me that the disease actually rose continuously over the parts of centuries..

 

Anybody please correct me in my logic..

 

Using process of elimination, I chose B.

 

Edited by Vipul Jain
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The reason I marked it as A is as follows:

 

If we have to strengthen the argument, we need to tell what has changed between 19th C and now that the Lyme disease has increased. The passage already suggests 3 things for the disease:

1) largely due to an increase in the deer population

2) growth of the suburbs

3) increased outdoor recreational activities in the deer's habitat

 

Here option A is the only option that compares before and after. I agree mid 20th C is not coherent with now but this was my train of thoughts before I eliminated B.

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