LSAT 152 | Section 1 | Logical Reasoning: Q10

LR Question 10 Explanation

QUESTION TEXT: When a bird flies, powerful forces converge on its shoulder joints …

QUESTION TYPE: Complete the Argument

ANALYSIS: The reasoning here is:

• During flight, powerful forces act on a bird’s shoulder joints.
• For flight to occur, the wings must be stable.
• Stability requires something to balance those forces.
• The only structure capable of balancing those forces is a certain ligament.

Once we learn that this ligament is the only thing that can stabilize wings, the conclusion has to be that the ligament is indeed how the bird stabilizes its wings.

___________

1. Too strong. The ligament is necessary to stabilize wings, but we don’t know that it’s the only thing that’s required. For example, wings are also required to fly.
2. This mixes things up. The ligament helps achieve stability. It’s not the reason stability is needed.
3. Unsupported. We only know it’s the only structure capable of balancing the forces, not that it’s the only connection anatomically.
4. The ligament is not the source of these powerful forces, it’s what helps balance these forces.
5. CORRECT. This is the valid inference. Since the ligament is the only structure capable of balancing the forces we need for wing stability, it must be the way that a bird stabilizes its wings.