PrepTest 132

Incorrect. This answer is trying to get you to think that the beak size didn't decrease, there was just a sampling flaw. Two issues there. First, it says that the small-beaked birds were easier to capture and measure, but that's a relative term. It still could have been quite easy, and almost just as easy, to capture the birds with the big beaks. Second, the stimulus states that the beaks of the wild birds decreased, and this answer would call that into question.

Incorrect. This answer is wrong for essentially the same reasons as (A). First, the relative term "easier" doesn't tell us that it was hard to capture the small-beaked birds, or even that it was all that much harder to do so. And second, the stimulus establishes the truth of the bird beak size change, so the ease of capture doesn't address the paradox.

Correct. Argument or Facts:
Facts

Question Type:
Paradox

Stimulus Summary:
Bird populations of the same species
Wild—Beak size decreased a lot
Captive—Beak size didn't change

Answer Anticipation:
This argument compares changes to the beak sizes of two different populations of a given bird species—one wild; one captive. The wild birds saw their beak size decrease substantially, while the captive one didn't see any changes.

Since this argument highlights a difference between two populations, we should look for a relevant difference that explains the discrepancy in beak size changes. Any difference between the wild and captive birds that can explain a beak size change is in play and should be fully considered. If you can anticipate something specific, great, but we have enough without a specific anticipation to head to the answer choices.

Answer Explanation:
This answer highlights a relevant difference between the captive birds and the wild ones. The food source for the wild ones changed, and it made it easier for small-beaked birds to survive. That explains why that population saw their beak size shrink. A captive bird population wouldn't have the same food source as the wild one, and so they wouldn't have the same pressure and their beak size wouldn't be expected to change.

Key Takeaway:
Paradox questions frequently have answers that are consistent with the information in the stimulus without answers the why? of it. These are tempting because it's easy to say, for example here, "Oh, well if the body size stayed the same, it makes sense that the beak size did, too." But making sense doesn't always provide the reason, and so these answers need to be eliminated.

Incorrect. While this answer might be consistent with the information in the stimulus, it doesn't explain why the change in the stimulus happened, so it falls short of addressing the question stem.

Incorrect. It's hard to see how this would explain anything without you assuming a whole lot of information here, so this answer is out of scope.