A distemper virus has caused two–thirds of the seal population in the North Sea to die since May 1988. The explanatio...

Irina on August 8, 2019

@Minerva,

This is a strengthen question, thus we are looking for a statement that would strengthen the argument's conclusion. The rest of the answer choices would weaken or have no impact on the argument.

The argument tells us that a normally latent virus has decimated the seal population in the North Sea and concludes that it must be severe pollution that weakened the seal's immune system.

Let's look at the answer choices:

(B) & (C) are incorrect because they suggest that severe sea pollution is unlikely and thereby, weaken the argument.

(D) is irrelevant, it makes no difference what seal species live in the region.

(E) is incorrect because it contradicts the premise - "a normally latent virus" suggests it is known to this population of seals.

(A) tells us that several other species in the area have experienced similar drops in population, suggesting that there must be a common cause that affects all the species in the region aside from a seal-specific virus. (A) is not a particularly strong answer choice, and on a real test, you are more likely to arrive at it by the process of elimination as it is the only one that slightly strengthens the argument.

Does this make sense?

Let me know if you have any further questions.