PrepTest 131, Section 2, Question 21
Essayist: When the first prehistoric migrations of humans(81 more words not shown)
Which one of the following,(7 more words not shown)
- AAnimals weakened by(19 more words not shown)
- BHuman beings generally(14 more words not shown)
- CVery few species(20 more words not shown)
- DIndividual humans and(12 more words not shown)
- ESome species of(23 more words not shown)
Reading the argument
The animals disappeared within 2,000 years of the humans' arrival. The essayist doubts that the small human groups could have hunted them into extinction and instead points to newly introduced microorganisms. That is one possible explanation. Why think it was the crucial one?
What about a changing climate? Imagine mammoths or saber-toothed tigers living in a cold habitat and then facing a much warmer environment. Or perhaps a disease arrived from another direction, such as South America. Those are possibilities to investigate, not claims about what actually happened here. They show why setting aside hunting doesn't by itself establish that microorganisms brought from Asia account for the extinctions.
What we’re looking for
To weaken the argument, I'd expect evidence for another explanation. Climate change would be one route. I'll also keep an eye on the essayist's dismissal of hunting: calling it implausible doesn't make evidence about its possible role irrelevant.
Working the answers
- A
This is compatible with disease playing a crucial role. Microorganisms needn't kill every animal directly; weakening animals so hunters or other predators can catch them would provide another way disease could contribute to extinction. A doesn't undermine the proposed importance of disease.
- B
The conclusion concerns the disappearance of North American animal species. Humans' immunity to diseases carried by other species doesn't tell us why those animals died out. Human resistance and animal vulnerability could both be present.
- CCorrect
This brings hunting back into the picture. Very few species that the newcomers didn't hunt became extinct in the period, suggesting that being hunted mattered to which species disappeared. That weakens the essayist's reason for dismissing hunting and assigning the crucial role to microorganisms. It doesn't say every extinct species was hunted or prove disease had no role, but it gives us reason to reconsider the competing explanation the essayist brushed aside.
- D
Healthy-looking carriers could still transport disease-causing organisms. That is consistent with the proposed route of disease arriving with humans and their animals. It doesn't offer a reason to think the microorganisms weren't crucial to the extinctions.
- E
Later extinctions are possible, but the argument concerns the species that disappeared within 2,000 years of the first migrations. Saying other species disappeared afterward doesn't explain what caused the earlier losses or undermine the proposed role of introduced microorganisms.
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