Critical Reasoning

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? and hence the number of people contracting Lyme disease�would likely decline.
Which of the following, if true, most strengthens the argument?
A. Ticks do not suffer any adverse consequences from carrying the bacterium that causes Lyme disease in humans.
B. There are no known cases of a human�s contracting Lyme disease through contact with white-footed mice.
C. A deer tick feeds only once while in the larval stage.
D. A single host animal can be the source of bacteria for many tick larvae.
E. None of the other species on which deer tick larvae feed harbor other bacteria that ticks transmit to humans.

OA is C .Can anybody pls explain why??

*Edit: Added spoiler*

100 ticks 100 mice ....

100 ticks 100 mice 900 others ..

all feed once... on 900 others..... no ticks get pick up the bacterium

Anon,
Isn't it that there is still a .1 possibility of a tick feed on a infected mouse?
I guess it should be E .Its strengthens the argument as other species being not affected by any other bacteria dont pose any danger.

"and hence the number of people contracting Lyme disease—would likely decline"

Lyme disease is caused by a bacterium transmitted to humans by deer ticks

Specific disease..specific bacterium

All we're looking at is a cause for decline in lyme disease among ticks and humans.

The less likely ticks are to feed on whitefooted mice, the less likely they are to carry lyme disease, the less likely humans are to get it.

C) If a deer tick feeds once and only once during the larval stage (when the ticks pick up the bacterium) then we can assume that the less white-footed mice are fed on, th eless the ticks will pick up the bacterium.
If the ticks fed twice or more, they could feed on white footed-mice at any time.

- But yes, E could be the correct answer b/c you have to assume that the other animals the ticks are eating do not have the disease.

I think E cannot be the answer because here we are concerned only with " decline in number of humans contracting lyme disease" ....." Whether other species transmit OTHER types of bacterium ' is clearly irrelevant to the Q.

I am convinced D is the answer.....but somehow not able to rule out B...

Because : If there are cases of human's contractiny lyme disease directly...
then "decreasing the likelihood of deer ticks that feed on white-footed mice" would really.....humans could still contract the disease directly from mice.

Well....THIS IS EXACTLY THE ASSUMPTION required in the Q.

Isnt it the assumption THAT STRENGTHENS the argument ??

Is "strengthening point " not an "assumption" of the argument, in general??

C...

if deer tick larva feed more than once then there might be more chances of their being feed on infected animal.

Hi!

In the passage, part of the author's evidence is that right now the deer tick larvae are picking up the bacteria that causes lyme disease by feeding on these infected white-footed mice. Because this is part of the author's evidence, this information must be true (in arguments, the evidence is "given" to the author).

The question stem tells us to treat the answer choices as "true"; in other words, as facts. Fact (C) tells us that they only feed once a year. If we put these two facts together we should be quite surprised. They only feed once, and yet they somehow manage to feed on these mice that transmit the bacteria.

This suggests that the reason they are feeding on these mice is a limited availability of the infection-free food sources rather than some alternative exlanation (such as preference). Fact (C), therefore, improves the likelihood of the plan's working; accordingly, it is a strengthener.

The other choices are either outside the scope or extreme (remember he was arguing that an increase in the supply of safe infection-free food sources would diminish the problem not negate it).

Not convinced with the OA. The fact that larvae feeds once doesnt not prove that it will feed on other species or the more of other species will not guarantee anyway that the larvae wont eat the white mice. E might also not be the case since it talks about other bacteria, but argument talks only about Lyme disease causing bacteria. Please clarify.