Logical reasoning PrepTest 140 · Section 3 · Question 25

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen

Stimulus Summary:
A survey shows that there's more wildlife in a national park after a development than there was before, so the new development hasn't hurt the wildlife. (Also, the park has enough resources to support the wildlife.)

Answer Anticipation:
First, the argument reaches an anti-causal conclusion (the development didn't cause harm to wildlife) based on a correlation, which is just as problematic but for slightly different reasons. Here, it's possible that the development did hurt wildlife, but other factors benefited them enough to balance it out. Any answer that rules out something balancing out damage from the development, or ruling out damage from the development, would strengthen this argument.

Second, the argument relies on comparing two studies, viewing changes in the results as indicating changes in reality. As such, it relies on the studies being similar in their methods and accuracy—anything that draws a relevant difference between the studies would weaken the argument, and anything that draws a relevant similarity will strengthen the argument.

Third, the argument uses an increase in the amount of wildlife to justify the conclusion that the development didn't adversely affect wildlife. There are more ways to hurt wildlife than just by decreasing the overall population—maybe it decreased diversity, or increased certain diseases. Any answer that rules out a potential adverse effect of the development that wouldn't decrease overall population would also strengthen this argument.

Finally, a note on that last sentence—what role does it serve? It takes one factor off the table. If the park didn't have the resources to support the current wildlife, then we'd have to worry about those resources and how they impact the wildlife. By stating that there are enough resources, we can ignore answers that deal with that (and also rule out the possibility that, in increasing wildlife population, the development adversely affected it because they could no longer be supported by the park system).

Answer Explanation:
If all species saw an increase in population, that rules out the possibility that the development hurt some species, allowing others to thrive. That possibility includes an adverse impact on certain species of wildlife, so ruling it out strengthens the argument that the development didn't have that adverse effect.

Key Takeaway:
There were a lot of issues with this argument, and those issues lead to both correct and incorrect answers. Since there's this variety, this is a great question to come back to and review as it'll help you learn about several concepts (anti-causal conclusions; using one metric to measure another; comparing studies).

Incorrect. If anything, questioning the comparison between the two studies would weaken the argument by suggesting they're comparing apples to oranges.

Incorrect. Note that the stimulus specifically stated that the park currently has enough resources to handle the increased population. Since the increased population in this answer hasn't actually exceeded the resources of the park, this answer doesn't affect the argument.

Incorrect. This answer questions the comparison between the old results and the new ones. If the new survey was more able to find hard-to-find animals, then the amount of wildlife may not have actually increased—the results are because the surveyors were able to find a higher percentage of the animals in the park. By questioning the comparison, this answer weakens the argument.

Incorrect. This answer choice brings up yet another relevant difference between the two surveys, thus undermining the argument. Even if you read this to mean there was a list of plant life but it didn't count towards wildlife totals, it would be an irrelevant difference and thus have no impact on the argument.