hi..
the para talks of overgrazing by large rabbit population and the use of a virus which will lower down the population of these rabbits. BUT there is some chance of a local herbivore getting infected. Therefore, the plan will reduce the rabbit population but will increase the threat to local species too.

Assumption-?

without looking at the choices, what can be the assumption for the argument-
1) herbivore cannot be vaccinated or protected against the virus.
2) If threat is INCREASING because of virus, the species are better with the existing system. And this system includes the overgrazing by enormous population of rabbit.
Ofcourse one-two more can be found but the above two will remain

point 2 is given by choice B..

lets see what other choices rae doing..

A) There is less chance that the virus will infect domestic animals on Tambor than that it will infect wild animals of species native to the island.
Out of scope. we are not interested in domestic animals here

B) Overgrazing by rabbits does not pose the most significant current threat to the bilby.
YEAH, point 2 above

C) There is at least one alternative means of reducing the rabbit population that would not involve any threat to the bilby.
The para is talking of a specific plan, so alternative mean will not effect the argument

D) There are no species of animals on the island that prey on the rabbits.
Again out of scope, we are talking of a specific case

E) The virus that the government proposes to use has been successfully used elsewhere to control populations of rabbits
Not necessary. it may be introduced in very small scale till now.
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The arguer concludes that the plan to reduce the rabbit population by introducing this virus will clearly increase the threat to local wildlife.
The arguer's evidence is that the there is a small chance that the virus could infect bilby population.

I think the small chance can be taken as a clue. So, okay, there is a small chance that the bilby population will be hurt be the population. But for this one piece of evidence to lead to the conclusion that the plan will increase the threat to local wildlife, we have to assume that introducing the virus wouldn't help local wildlife in some way that would be more significant than this small threat of infecting the bilby. In fact, we have to assume that the plan won't help the bilby itself in some way that would prove more significant than the small threat.

That's a direct match for answer choice B.

If we don't have a clear prediction, we can use the denial test:

Denying B we get, 'Overgrazing by the rabbits DOES pose the greatest threat to the bilby population." If this were the case, then introducing the virus would reduce the most significant threat. So even though it would pose a small threat itself, overall the plan would actually help the bilby. So, when we deny B, the arg falls apart. Therefore B must be an assumption of the argument.

Here are my views--

Option (A)--Irrerelevant.Even if it infects domestic animals less and wil animals more it is not an assumption on which the conclusion is stated.Out
Option (B)--Good.Keep it.
Option ©--So what if there is.We need an assumption whereas this states another remedy.Out of Scope.Out.
Option (D)--Even if there is any its not an assumption used in the argument.Out of Scope.Out.
Option (E)--Its already been stated in the argument and thus is not an assumption.Out.

OA is 'B'.

B for.me as well ...what's the OA

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Conclusion : The government's plan might be successful to reduce the population of Rabbits but it will clearly increase the threat to native wildlife.

Introduction of Rabits >> Overgrazing
Overgrazing >> Impact on native wildlife ??
if there is any impact , then Overgrazing would have increased the threat to native wildlife not the government's plan.
Hence the assumption is that there is no other factor which will cause negative impact on native wildlife apart from the government's plan.

Ans : B

chetan2u

Can you please explain this ?
_________________

Hello,

The question states that:
1) Someone put rabbit in an region
So 2) Overgrazing by rabbits are threatening agriculture

3) Government people think: let's kill the rabbit introducing a virus
But 4) This virus can also threat the bilby, a native animal

Conclusion: the government plan will not only threat rabbit but also the bilby ('clearly')

What if the bilbies have been already threatening by the rabbits? So, the problem would be not the government's virus, but the rabbits themselves.

Thus, the author, in order to make his/her conclusion, assumes that the bilby is not currently threatened by rabbits.

Best,

Hi VeritasKarishma, if you can please provide explanation on the above question and why B is the answer? Didn't quite get it.
Thanks a lot.

Overgrazing by rabbits is harming agriculture.
Plan is to introduce a virus that will reduce rabbit population.
There is a small chance that the virus will infect bilby (native wildlife) too.

Conclusion: Plan may help agriculture but will clearly INCREASE threat to native wildlife.

Our conclusion says that the threat to native wildlife will increase because of the introduction of virus. So whatever is the threat to native wildlife right now, it will increase by the introduction of the virus. What is our assumption here?


A) There is less chance that the virus will infect domestic animals on Tambor than that it will infect wild animals of species native to the island.
Irrelevant. Comparison with domestic animals are out of scope. We are talking about wildlife only.

B) Overgrazing by rabbits does not pose the most significant current threat to the bilby.
Correct. We are concluding that threat will increase. What if overgrazing is a huge threat right now which could affect the bilby population badly? Then introducing the virus may actually reduce the threat - after all, there is a small chance that the virus will affect bilby. Introducing the virus will eliminate the overgrazing threat and introduce a small chance that the virus could affect bilby. So it is possible that introducing the virus may decrease the overall threat to wildlife.

C) There is at least one alternative means of reducing the rabbit population that would not involve any threat to the bilby.
Irrelevant. We are discussing the merits/demerits of this plan.

D) There are no species of animals on the island that prey on the rabbits.
If there are some species that prey on the rabbit, introducing the virus may reduce their food supply. So the wildlife may suffer. Hence our conclusion becomes stronger, if anything.

E) The virus that the government proposes to use has been successfully used elsewhere to control populations of rabbits.
We don't know and it doesn't matter. The virus has caused epidemic in rabbit population and that's all.

Answer (B)
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Assumption-?

without looking at the choices, what can be the assumption for the argument-
1) herbivore cannot be vaccinated or protected against the virus.
2) If threat is INCREASING because of virus, the species are better with the existing system. And this system includes the overgrazing by enormous population of rabbit.
Ofcourse one-two more can be found but the above two will remain

point 2 is given by choice B..

lets see what other choices rae doing..

A) There is less chance that the virus will infect domestic animals on Tambor than that it will infect wild animals of species native to the island.
Out of scope. we are not interested in domestic animals here

B) Overgrazing by rabbits does not pose the most significant current threat to the bilby.
YEAH, point 2 above

C) There is at least one alternative means of reducing the rabbit population that would not involve any threat to the bilby.
The para is talking of a specific plan, so alternative mean will not effect the argument

D) There are no species of animals on the island that prey on the rabbits.
Again out of scope, we are talking of a specific case

E) The virus that the government proposes to use has been successfully used elsewhere to control populations of rabbits
Not necessary. it may be introduced in very small scale till now.
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I selected Answer A with the logic that domesticated animals fall into the category of "agriculture." Therefore, the risk to agriculture is low and has potential benefits while the risk to wildlife, which includes the Bilby that was discussed, is high. Would you mind explaining if there is something I am missing that makes this answer is incorrect?

Thank you!