souvik101990 wrote:
Source : GMATPrep Default Exam Pack
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 from feeding on infected whitefooted mice. However, certain other species on which the larvae feed do not harbor the bacterium. Therefore, if the population of these other species were increased, the number of ticks acquiring the bacterium would likely decline.
Which of the following would be most useful 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.
Dear
mikemcgarry,
MagooshExpert,
GMATNinjaTwo,
GMATNinjaThanks in advance for reading my post,
Although reading for several hours, I am still confused a lot,
First,
I am not sure i completely understand the prompt.
The conclusion is
if the population of these other species were increased, the number of ticks acquiring the bacterium would likely decline , however, how could the number of infected deer ticks reduce? The number of infected deer ticks is a fact, it cannot change, right?
I read some explanations of decline, such as dilute or disperse number of infected deer ticks, but i dont think they are compelling, because i thought these thoughts are like density, which is not the same as decline. Additionally, the prompt does not mention any number of any territories.
furthermore, review the conclusion,
the number of ticks acquiring the bacterium..., here
acquiring is modifier, if the deer ticks were infected, why not the modifier is acquired, so i think
acquiring does not mean the infected deer ticks, but those may be infected in the future if introduce the certain species on which the larvae feed.
Secondback to the whole question,
Premise 1, larvae carry bacterium if they fed white - foot mice,
Premise 2, a certain species without bacterium can be food of larvae
Conclusion, if introduce the certain species, the number of deer ticks acquiring will decline.
My assumption is
maybe larvae have not enough food or have no choice but feed mice.
I think i should find a answer that can describe my assumption. (A), (B), (D) confused me a lot
(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.
I picked up this one.
here is my reasoning:
I did not neglect "
ONLY", but i don't think
ONLY will be a solid reason to eliminate
If the certain species live in the same place as the mice live, implying there are food without bacterium for larvae, except mice. so maybe there are other factors that larvae feed mice rather than lack of certain species.
if the certain species are found other place where mice don't live, then introducing uninfected species will provide the food for larvae, making the conclusion more likely.
That's why i picked it up.
BTW, the opposite of "ONLY" is "NOT ONLY", if species live in place A, the opposite is the spices live in any place except place A , right?
(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.I still cannot understand how B affects "
the number of ticks infected by the bacterium...",
(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.
This one, many explanations say it is irrelevant.
seems i did not get why irrelevant, although i did not choose it.
If the deer ticks will become to carry bacterium even though they were uninfected at larvae stage, then, introducing certain species does not work.
If the deer ticks will not become to carry bacterium even though they were uninfected at larvae stage, then, introducing certain species would expand the food source for larvae, it helps the conclusion.
Genuinely
Thanks again in advance.
Have a nice day
>_~