PrepTest 135, Section 1, Question 18
Zoologist: Every domesticated large mammal species now in(50 more words not shown)
The zoologist's argument requires the(2 more words not shown)
- Ain spite of(18 more words not shown)
- Bit is not(15 more words not shown)
- Cnot all of(14 more words not shown)
- Dthe easier it(16 more words not shown)
- Eof all the(18 more words not shown)
Reading the argument
The history makes the zoologist's conclusion sound plausible at first. People repeatedly tried to domesticate the wild species that seemed useful, yet all the domesticated large mammal species still around were domesticated thousands of years ago. Perhaps the species left wild really are difficult to domesticate or not worth the effort.
I'd still look for another possibility. Could some species have been inaccessible to earlier people, or appeared only recently? Those are speculative guesses, and the stated history of repeated attempts makes the access idea a poor fit for the species people thought worth domesticating. I don't yet have a clean explanation for why the zoologist is wrong.
What we’re looking for
That's fine for a necessary-assumption question. We can examine what the argument needs without forcing an objection that fights its evidence. Keep the conclusion in view: most wild large mammal species today would be difficult to domesticate or not worth domesticating. Which unstated assumption does that judgment require?
Working the answers
- A
The argument says people tried repeatedly with species that seemed worth domesticating. It doesn't require attempts with every species, including those nobody thought worthwhile. The conclusion expressly allows that some species are still wild because they wouldn't be worth domesticating, rather than because people tried and failed.
- BCorrect
Here's the possibility I hadn't accounted for: domesticating animals could be much easier now. Past failures don't establish present difficulty if our methods have improved greatly. Imagine new techniques that let people manage animals their ancestors couldn't successfully domesticate. Those animals could be both useful and comparatively easy to domesticate today.
The zoologist relies on the older record to judge today's possibilities. That requires treating the difficulty as sufficiently comparable across time, rather than overlooking a major improvement that would undermine the inference.
- C
Some previously domesticated species might have become extinct. That doesn't establish whether the wild species alive today would be easy or worthwhile to domesticate. The argument doesn't need a claim about the extinction of domesticated species to make its point about current wild ones.
- D
Ease and value needn't rise together. A species could be hard to domesticate but very valuable once domesticated; another could be easy but offer little benefit. The zoologist treats difficulty and lack of value as alternative explanations, without needing a rule that connects their degrees.
- E
The argument doesn't rank the surviving domesticated species by either difficulty or date. The earliest ones needn't have been the easiest. What matters is the inference about species still wild today, not the order in which the already domesticated species were brought under human control.
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