Critical Reasoning

Thirty years ago, deer and elk in selected parts of the Rocky Mountains were first discovered with a condition known as wasting disease. In 1970, two percent of the deer and elk killed by hunters were diagnosed with the disease. In 1995, that percentage had grown to six percent. This increase in the incidence of the disease proves that wasting disease has become much more prevalent in the last twenty-five years.

If true, which one of the following selections most seriously weakens the author's conclusion?

(A) Wasting disease has not been discovered in domestic livestock or in moose or bighorn sheep, which are also found in significant numbers in the Rocky Mountains.
(B) Wasting disease tends to make deer and elk lethargic, making them more easily killed by hunters.
(C) Since it was first reported, wasting disease has occasionally been diagnosed in deer outside the Rocky Mountains.
(D) Hunters have grown more reluctant to cooperate with the authorities in reporting their deer and elk harvest, because if wasting disease is diagnosed in their harvest, the meat will be destroyed.
(E) It is very difficult to diagnose wasting disease more than twenty-four hours after death, so many cases of the disease have gone undiagnosed.

OA : after some time

IMO B

The argument has to be weakened so i need to find an evidence that tells us that the disease has not become prevalent but the hunting has increased that makes people think that incidence of disease has increased . Option B hits perfectly as it tells that the disease makes the animals lithargic and hence are hunted more than before , its the hunting which has increased not the disease .

Its between D and E .The Rest of the choices delve into irrelevant things.
D makes it seem as if the Hunters have begun to conceal the Diagnosis Just Now and 25 years back they used to report the correct incidence. So This strengthens the Conc instead of Weaken . In E , the incidence of the Disease in both the cases 1970 and 1995 has been understated

AIM GMAT wrote:IMO B

The argument has to be weakened so i need to find an evidence that tells us that the disease has not become prevalent but the hunting has increased that makes people think that incidence of disease has increased . Option B hits perfectly as it tells that the disease makes the animals lithargic and hence are hunted more than before , its the hunting which has increased not the disease .

But B doesn't say that the disease made these animals lethargic only in 1995.
If the disease makes animals lethargic,then it could have had the same impact even on the animals in 1970.

In E , the incidence of the Disease in both the cases 1970 and 1995 has been understated

Even if the figures were understated in both 1970 & 1995 , it doesn't weaken the conclusion that "The disease has become more prevalent in past 20 years"
E doesn't say that most of the cases in 1970 had gone undiagnosed.

prachich1987 wrote:

In E , the incidence of the Disease in both the cases 1970 and 1995 has been understated

Even if the figures were understated in both 1970 & 1995 , it doesn't weaken the conclusion that "The disease has become more prevalent in past 20 years"
E doesn't say that most of the cases in 1970 had gone undiagnosed.

In 1970 if there were 10 actual cases of Wast. Dis.
But only 2 were reported
In 1995 if there were 8 actual cases But only 6 were reported
The conclusion is Undermined

According to Adam , The answer to a weaken question does not destroy the conclusion but makes it more difficult for us to come to the conclusion from the Evidence.

mundasingh123 wrote: In 1970 if there were 10 actual cases of Wast. Dis.
But only 2 were reported
In 1995 if there were 8 actual cases But only 6 were reported
The conclusion is Undermined

It doesn't rule out the below possibility but

In 1995 if there were 10 actual cases of Wast. Dis.
But only 2 were reported
In 1970 if there were 8 actual cases But only 6 were reported
The conclusion is NOT undermined.

Even I had marked E first
But that is not the OA.

LOL Then It has to be D but i dont know how we should interpret " Have Grown "

Anyways whats the OA ? Do u have any explanations for the OA ?

I guess we need expert opinion over here , its getting confusing .

mundasingh123 wrote:LOL Then It has to be D but i dont know how we should interpret " Have Grown "

In any case , it CANNOT be D.
D says the hunters have grown more reluctant. So it means even more than 6% were diagnosed with the disease.But they didn't report so for fear of losing business.

Now you are left with three options A,B,C

prachich1987 wrote:

mundasingh123 wrote:LOL Then It has to be D but i dont know how we should interpret " Have Grown "

In any case , it CANNOT be D.
D says the hunters have grown more reluctant. So it means even more than 6% were diagnosed with the disease.But they didn't report so for fear of losing business.

Now you are left with three options A,B,C

Thats the reason why i elimnated D in the first case.Another way in which u can interpret "have grown " is the hunters grew reluctant in 1970 itself . I posted in accordance with this interpretation

OA plz.

prachich1987 wrote:Thirty years ago, deer and elk in selected parts of the Rocky Mountains were first discovered with a condition known as wasting disease. In 1970, two percent of the deer and elk killed by hunters were diagnosed with the disease. In 1995, that percentage had grown to six percent. This increase in the incidence of the disease proves that wasting disease has become much more prevalent in the last twenty-five years.

If true, which one of the following selections most seriously weakens the author's conclusion?

(A) Wasting disease has not been discovered in domestic livestock or in moose or bighorn sheep, which are also found in significant numbers in the Rocky Mountains.
(B) Wasting disease tends to make deer and elk lethargic, making them more easily killed by hunters.
(C) Since it was first reported, wasting disease has occasionally been diagnosed in deer outside the Rocky Mountains.
(D) Hunters have grown more reluctant to cooperate with the authorities in reporting their deer and elk harvest, because if wasting disease is diagnosed in their harvest, the meat will be destroyed.
(E) It is very difficult to diagnose wasting disease more than twenty-four hours after death, so many cases of the disease have gone undiagnosed.

OA : after some time

OA B

Its a bit convoluted language. Options D & E actually indicate that the incidence of disease is even greater. Option B states that majority of the ones killed are because they are infected with disease which has in turn lead to its kill. Thus B is the correct answer.

thanx