PrepTest 132

Incorrect. The purpose of the wings and fins has to be similar, but how they developed doesn't. Additionally, in talking about "many physical features" instead of just the one, this answer has too wide a scope to be necessary.

Incorrect. If these other dinosaurs had long, thin fins and also hunted their prey over long distances, then the argument could still work.

Incorrect. The argument concludes that Ps hunted their prey over long distances, not that they needed to hunt their prey over long distances, so this answer choice is incorrect in establishing it as necessary—especially necessary for a specific reason not mentioned in the stimulus.

Incorrect. Even if most aren't, it's possible that this one is, so this answer is too strong.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Necessary Premise

Stimulus Summary:
P fins are similar to bird wings specialized for long flight, so Ps probably chased their prey over long distances.

Answer Anticipation:

Answer Explanation:
This answer establishes that the similarity between the fin and the wing isn't just in shape, but also in function. Since the conclusion is about function, it's necessary to know that the comparison touches on that issue. If the shape of a fin has a different effect on swimming than the shape of a wing has on flying, then the comparison the argument relies on as (essentially) it's only premise isn't relevant to the conclusion, and the argument falls apart.

Key Takeaway:
When an argument relies on a similarity to prove its point, that similarity has to be established as relevant to the conclusion. Here, the shape of two things are compared, but there's no indication that the shape is related to movement/hunting. Whenever thinking about comparisons in an argument, always consider whether it's necessarily relevant.