Lyme Disease - Tougher Version

[BUGGS]

I Got this question on my New GMATPREP software's Exam -2 today.
There is another version of this question, but this one has tougher and close option choices.
Lyme disease is caused by a bacterium transmitted to humans by deer ticks. Generally, deer ticks pick up the bacterium while in the larval stage by feeding on infected white-footed mice. However, certain other species on which the larvae feed do not harbor the bacterium. If the population of these species increased, more of the larvae would be feeding on uninfected hosts, so the number of ticks acquiring the bacterium would likely decline.

Which of the following would it be most important to ascertain in evaluating the argument?

(A) Whether populations of the other species on which deer tick larvae feed are found only in the areas also inhabited by white-footed mice.
(B) Whether the size of the deer tick population is currently limited by the availability of animals for the tick's larval stage to feed on.
(C) Whether the infected deer tick population could be controlled by increasing the number of animals that prey on white-footed mice.
(D) Whether deer ticks that were not infected as larvae can become infected as adults by feeding on deer on which infected deer ticks have fed.
(E) Whether the other species on which deer tick larvae feed harbor any other bacteria that ticks transmit to humans

[kyle_proctor]

Tough question.

1) Lyme is caused by bacteria transmitted from deer ticks
2) Ticks become infected when munching on white-footed mice
3) Ticks also feed on other species w/o bacteria

Argument continues.....

If the species w/o bacteria were to increase, more deer tick larvae would feed on them. Therefore, the number of ticks acquiring the bacteria would decline.


I thought about it like this. Let's say that deer tick larvae never again feed on an infected white-footed mouse. Does this mean that deer ticks would never again acquire the disease? Perhaps.

What if fully-grown deer ticks, who DO NOT have the bacteria, could just as easily become infected with the disease by feeding on deer who have been attacked by infected deer-ticks. We assume here that the clean deer-ticks would acquire the disease simply by munching on actual deer.


If this were true, our conclusion: "so the number of ticks acquiring the bacterium would likely decline" does not seem too valid.

I would settle on "D". Very hard question to wrap my head around. Let's see what the experts say.

[kyle_proctor]

Hey BUGGS

Search the forums for this one. Ron explains it well. My reasoning above is correct but brings me to the wrong answer.

FYI

[BUGGS]

Hey BUGGS

Search the forums for this one. Ron explains it well. My reasoning above is correct but brings me to the wrong answer.

FYI

Hi Kyle,
I did a random google search for this question and every time, it leads me to the other Question,the one with same argument but different easier options.

But thanks for your effort!!!

[BUGGS]

Tough question.

1) Lyme is caused by bacteria transmitted from deer ticks
2) Ticks become infected when munching on white-footed mice
3) Ticks also feed on other species w/o bacteria

Argument continues.....

If the species w/o bacteria were to increase, more deer tick larvae would feed on them. Therefore, the number of ticks acquiring the bacteria would decline.

Your above reasoning has made me ponder over the argument and
now when I read these lines from the argument -"certain other species on which the larvae feed do not harbor the bacterium. If the population of these species increased, more of the larvae would be feeding on uninfected hosts, so the number of ticks acquiring the bacterium would likely decline.

I am inclined to pick option [B] over all others, since the conclusion is assuming that if population of those special species increase, more larvae would feed on uninfected hosts, it makes us imperative to know whether there are such species available or in other sense what [B] suggests - "Whether the size of the deer tick population is currently limited by the availability of animals for the tick's larval stage to feed on."

I think, B connects that gap very well.

Hope my writing above is clear for you to understand.

[RonPurewal]

rc-lyme-disease-gmatprep-t7861.html

post on that thread, not here. this thread is now locked.