imyhpark wrote:Rabbits were introduced to Numa Island in the nineteenth century. Overgrazing by the enormous population of rabbits 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 chance that the virus will infect the bilby, an endangered native marsupial. The government's plan, therefore, may serve the interests of agriculture but will clearly increase the threat to native wildlife.

imyhpark wrote:Rabbits were introduced to Numa Island in the nineteenth century. Overgrazing by the enormous population of rabbits 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 chance that the virus will infect the bilby, an endangered native marsupial. The government's plan, therefore, may serve the interests of agriculture but will clearly increase the threat to native wildlife.

Which of the following, if true, most seriously weakens the argument?
A. There is less chance that the virus will infect domestic animals on Numa than that it will infect bilbies.
- There is no information as to how the virus is going to affect the other native animals on the island.
B. There are no species of animals on the island that prey on the rabbits.
- This info may be correct but not to our interest here,our agenda here is the effect of virus on bibly.
C. Overgrazing by rabbits endangers many of the plants on which bilbies feed.
- This indicates that even if virus is not introduced, bilbies are anyway going to die and rabbit population will continue
to increase. This certainly weaken the conclusion part - 'increase the threat to native wildlife' as threat exists anyway.
D. The virus that the government proposes to use has been successfully used elsewhere to control populations of rabbits.
- Population of rabbit may have been controlled but here the agenda is to save bilby population.
E. There is no alternative means of reducing the rabbit population that would involve no threat to the bilby.
- This is strengthening the conclusion towards the use of virus.

So,IMO : C