Logical reasoning PrepTest 110 · Section 3 · Question 24

Incorrect. The relative number of non—native predator species doesn't matter—even the absolute number of species is out of scope. What matters is how many of the opossums are killed by those predators, and even a single non—native species could still kill quite a few native animals.

Incorrect. There are enough foxes around to hunt down a significant number of opossums, so how well they adapted to the Australian climate compared to other species is out of scope.

Incorrect. This answer can feel like it eliminates an alternative cause, or provides evidence against the alternative hypothesis presented. However, that alternative mentioned a scarcity of food, so the type of food fed to the captive opossums is out of scope.

Incorrect. This answer seems to be addressing the alternative theory, but how many species competing for food that are native to Australia doesn't matter—just whether there are enough of these species to lead to a scarcity of food.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen

Stimulus Summary:
Phenomenon 1 — Ringtail opossums* are endangered
Study results — 75% of ringtail opossums raised in captivity were killed by non—native foxes
Old Explanation — Scarcity of food led to opossums becoming endangered
Author's Explanation — Non—native predator species led to opossums becoming endangered

Answer Anticipation:
This argument is set up as a phenomenon/explanation passage. It brings up the endangered nature of the ringtail opossums, and then it presents an old explanation and a new explanation. We're tasked with strengthening the new explanation—that non—native predators hunted the opossum into being endangered.

What supports that explanation? The results of a study—75% of ringtail opossums raised in captivity released into the wild were killed by foxes. That does seem like a pretty high rate! However, any argument that brings up a study potentially has a sampling flaw. And in this case, the study was done on opossums raised in captivity—presumably, they didn't need to learn how to avoid predators when growing up in a zoo. They're not, therefore, representative of the opossums raised in the wild. If the percentage of opossums raised in the wild that are killed by non—native species is about the same as the raised—in—captivity ones, then the predator theory makes sense; if it's much lower, then it doesn't.

Let's find an answer establishing the representativeness of the data/sample from the study.

Answer Explanation:
This answer establishes that, on the metric of getting killed by foxes, the raised—in—captivity opossums are representative of raised—in—the—wild opossums. If the wild ones are "no more successful" in defending themselves against foxes than the captive ones then that 75% number should be met (or exceeded) by the wild group thus suggesting that the species may have been hunted by predators onto the endangered species list but foxes a non—native species.

Key Takeaway:
Harder questions don't necessarily have harder logic—sometimes they just hide that logic better. When you strip everything else away there's a pretty clear Sampling Flaw here with a study done on how frequently predators catch captive animals of a certain species used to justify a conclusion about that species generally. Remember—when you identify an element in an argument that is commonly associated with a specific flaw take the time to think about whether that flaw is present!

*Don't go down the rabbit hole of looking into possum vs. opossum. People care a lot about these names!