PP1 (Shorter) Verbal Section 2 (Hard) Q13

The Process

This is a Critical Reasoning question, as indicated by the phrases "if true" and "strongly supports the argument". We need to follow a process for these questions.

Step 1: Identify the CONCLUSION of the argument.

  • Conclusion: The increased flow from building houses is likely responsible for the dusky salamander's disappearance.

Step 2: Identify the REASON(S) the author has identified to support their conclusion.

  • Reason/Evidence: The dusky salamander lives only in slow-moving streams where organic stuff can settle and gather. However, rainwater now runs directly into streams, causing faster flow.

Step 3: Engage in a LOGICAL LEAP that supports the conclusion. 

  • Logical Leap: So, the dusky salamander only likes slow-moving water and the water is now fast. That's bad for the dusky salamander but doesn't necessarily mean that's what caused it to disappear. Maybe there was pollution? Or a disease of some sort? If we really want to support this argument, we need to eliminate these other factors. What if there was another species of salamander that likes both slow-moving and fast-moving water? If that other salamander was thriving, then we can eliminate causes like pollution or disease and pinpoint the water flow as the main issue.

The Right Answer

C: This choice matches one of our logical leaps above. If the two-line salamander likes both slow and fast-moving streams and has been unaffected by the suburban development, then we can conclude it's most likely the fast-moving streams that are causing the issue for the dusky salamander and not some other factor.

The Wrong Answers

  • A: This information is irrelevant because it doesn't reference the key piece of evidence from the passage: the water flow.

  • B: This information weakens the author's conclusion. If the dusky salamander has disappeared from some suburban areas developed over 100 years, then clearly some other issue is at play. They tolerated the fast-moving streams for 90 years -- why are they suddenly dying?

  • D: This answer choice weakens the conclusion by providing another cause (pollution) for the dusky salamander's disappearance.

  • E: This answer choice weakens the conclusion because it eliminates the suburban development as a cause for the dusky salamander's disappearance. If much of the development happened in areas that are NOT prime habitat for the dusky salamander, then why is the dusky salamander disappearing? It must be some other factor.