PyjamaScientist wrote:
Hi
AndrewN &
MartyTargetTestPrep,
This question got me thinking a lot. As it's a strengthen type question, we need to add weight to the conclusion or provide a new piece of information that affirms the causality of the argument.
But,
frankly, none of the choices seems to do that for me. I zeroed on (D) after POE. All the choices were not even relevant to the argument. But, (D) too, barely strengthens the cause-effect relationship stated in the conclusion.
The author's conclusion is:
"it is likely that diallyl sulfide from the garlic repelled the mosquitoes", we need information that strengthens this idea. But, (D) instead brings in a piece of information that has no bearing on the conclusion. (D) says that,
"Many insect species not repelled by diallyl sulfide were found in the flooded garlic fields throughout the summer." Fine. But, does that strengthen the point that
"diallyl sulfide repelled the mosquitoes"? I feel there's still a gap and (D) does not bridge any.
The correct answer should have had something that really "increased my belief" into the statement that
"diallyl sulfide DID repel the mosquitoes", does the information provided in (D) do that? I am not sure how.
Choice (D) provides a bit more reason to believe that "diallyl sulfide repelled the mosquitoes" by showing, in cases of insects on which diallyl sulfide has no repellent effect, there was no repellent effect.
In other words, since "flooded fields would normally attract mosquitoes," it stands to reason that SOMETHING repelled mosquitoes. OK, so, since the fields were garlic fields, maybe diallyl sulfide repelled mosquitoes.
Then, (D) says, "Many insect species not repelled by diallyl sulfide were found in the flooded garlic fields throughout the summer."
So, whatever repelled mosquitoes did not repel those insects.
That information allows us to eliminate some things that would have repelled a wider spectrum of insects, such as naphthalene or a fuel spill, giving us more reason to believe that it was indeed diallyl sulfide and not something else that caused there to be no mosquitoes in the fields.