Rabbits were introduced to Tambor Island in the nineteenth century.

Rabbits were introduced to Tambor Island in the nineteenth century. Overgrazing by the enormous rabbit population now menaces the island's agriculture. The government proposes to reduce the population by using a virus that has caused devastating epidemics in rabbit populations elsewhere. There is, however, a small chance that the virus will infect the bilby, an endangered native herbivore. The government's plan, therefore, may serve the interests of agriculture but will clearly increase the threat to native wildlife.

The argument above assumes which of the following?

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.
B) Overgrazing by rabbits does not pose the most significant current threat to the bilby.
C) There is at least one alternative means of reducing the rabbit population that would not involve any threat to the bilby.
D) There are no species of animals on the island that prey on the rabbits.
E) The virus that the government proposes to use has been successfully used elsewhere to control populations of rabbits.

Rabbits were introduced to Tambor Island in the nineteenth century. Overgrazing by the enormous rabbit population now menaces the island's agriculture. The government proposes to reduce the population by using a virus that has caused devastating epidemics in rabbit populations elsewhere. There is, however, a small chance that the virus will infect the bilby, an endangered native herbivore. The government's plan, therefore, may serve the interests of agriculture but will clearly increase the threat to native wildlife.

The argument above assumes which of the following?

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.
B) Overgrazing by rabbits does not pose the most significant current threat to the bilby.
C) There is at least one alternative means of reducing the rabbit population that would not involve any threat to the bilby.
D) There are no species of animals on the island that prey on the rabbits.
E) The virus that the government proposes to use has been successfully used elsewhere to control populations of rabbits.

Rabbits were introduced to Tambor Island in the nineteenth century. Overgrazing by the enormous rabbit population now menaces the island's agriculture. The government proposes to reduce the population by using a virus that has caused devastating epidemics in rabbit populations elsewhere. There is, however, a small chance that the virus will infect the bilby, an endangered native herbivore. The government's plan, therefore, may serve the interests of agriculture but will clearly increase the threat to native wildlife.

The argument above assumes which of the following?

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.
B) Overgrazing by rabbits does not pose the most significant current threat to the bilby.
C) There is at least one alternative means of reducing the rabbit population that would not involve any threat to the bilby.
D) There are no species of animals on the island that prey on the rabbits.
E) The virus that the government proposes to use has been successfully used elsewhere to control populations of rabbits.

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)

Bunuel, this is a Gmatprep question, can you tag? Thanks!

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!

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)

Hi KarishmaB,

Love your explanations. Always on point!


In this question though, I have a doubt. How are we inferring a comparison between the threat levels of overgrazing and of a viral epidemic? Choice B says "most significant current threat", and the stimulus says "a small chance of viral infection". Now, can't the most significant current threat be lower in degree of threat than "a small chance of viral infection"? In your explanation, you have equated "most significant threat" to "a huge threat". Isn't "most" a relative term, which need not mean "huge"?
So, if I'm correct, how are we inferring that "most significant current threat" will "certainly" be greater than "a small chance of viral infection"? Are we using a contrast between "significant" and "small", and ignoring the governing impact of "most"?

Also, in your explanation, you've used the words "may" and "possible" in the conclusion. However, in the stimulus, the conclusion says "will definitely increase the threat". So, this doesn't seem to be a case of a "likely" conclusion either. Had it been one, then there wouldn't have been a need for this debate.

A valid necessary assumption, in my modest opinion, would be that the threat of overgrazing must not be greater than the threat of viral epidemic. We don't "need" overgrazing to not be the "most significant" threat or even "least significant". Even if it is "the most significant threat", it could still be lower in degree than the threat of a viral epidemic.

I hope I have been able to put my point across. I'm trying to identify whether I've missed some important clue.

Looking forward to the discussion.

Thanks and regards,