Logical reasoning PrepTest 152 · Section 1 · Question 10

While this argument tells us one requirement for flight (balancing certain forces), it doesn't establish that as the only requirement. Unless you're an ornithologist (yes, we're getting fancy with our science terms in these explanations), you have no means of analyzing this answer, so it can't complete this argument.

This answer reverses the "direction" of the argument. The ligament stabilizes the forces; it isn't what makes this stabilization necessary.

This is too strong. While we know that it's the only connection strong enough to balance the forces of flight, there may be other connections that serve other purposes.

Again, this reverses the "direction" of the argument. The ligament doesn't cause the forces; or, at least, it doesn't cause all of them. It balances those forces.

Correct. Argument or Facts:
Facts

Question Type:
Argument Completion

Stimulus Summary:
Birds must stabilize a lot of pressure to fly. The pressure must be balanced. The only thing that can balance it is this one ligament. Therefore . . .
Answer Anticipation:
It must be the ligament that balances the pressure and stabilizes the bird. For these Argument Completion questions, the conclusion almost always wraps up the argument by bringing all the premises together—don't expect to leave anything out or bring in any new information.

Answer Explanation:
The bird must stabilize its wings, and this ligament is the only thing in town strong enough to do so. Therefore, it must be what does it.

Key Takeaway:
For Argument Completion questions, beware answers that bring up all the relevant ideas but in a way that doesn't "flow" with the argument itself.