Logical reasoning PrepTest 107 · Section 3 · Question 8

Incorrect.

Incorrect. This answer suggests an alternative cause for the lower proportion of pears lost to insect damage—an insect-abatement program. In suggesting an alternative cause, this answer weakens the argument.

Incorrect. This answer suggests an alternative cause for the lower proportion of pears lost to insect damage—birds are eating more of the insects. In suggesting an alternative cause, this answer weakens the argument.

Incorrect. This answer suggests an alternative cause for the lower proportion of pears lost to insect damage—the habitat of the pear-eating insects is shrinking, so there are likely fewer of the insects around. In suggesting an alternative cause, this answer weakens the argument.

Incorrect. This is a tricky answer! However, it brings up an alternative explanation of what's going on. It's not that the new pesticide by itself is more effective, but rather that the old pesticide has persisted and is still working, and the new pesticide is adding effects on top of that. As such, it's impossible with the information we have to disentangle the effects of the two pesticides, so we can't conclude that the new one is more effective, thus weakening the argument.