PrepTest 105, Section 4, Question 20
James: Chemists have recently invented a new technique(74 more words not shown)
Marta responds to James's argument(1 more words not shown)
- Acasting doubt on(13 more words not shown)
- Bquestioning the credibility(5 more words not shown)
- Cindicating that James(12 more words not shown)
- Dpointing out a(12 more words not shown)
- Epointing out that(10 more words not shown)
Reading the argument
Getting a useful material out of nuclear waste sounds promising. Rhodium helps make catalytic converters, and those converters remove harmful gases from car exhaust. I can see a possible environmental benefit.
But are manufacturers using the new technique? What if it costs too much to be worthwhile? Discovering a way to extract rhodium doesn't by itself establish that this discovery is already helping clean up exhaust. James needs the useful possibility to have become an actual contribution.
Marta identifies that exact gap. She accepts that the technique works, but says it remains experimental. The rhodium used to manufacture catalytic converters still comes from the same sources as before. So James can't point to this new extraction technique as evidence of a contribution already being made in that manufacturing process.
What we’re looking for
The question asks how Marta responds. She supplies a fact James overlooked: effective in an experiment doesn't mean adopted for current production. She can accept his description of the invention and its possible use while challenging the conclusion he draws from them.
Working the answers
- A
Marta doesn't deny that chemists invented an effective extraction technique or that catalytic converters remove harmful gases. She adds information about whether manufacturers have adopted it. The supporting claims can be accurate while James's conclusion goes too far. That's why calling her response a challenge to those claims misses the distinction.
- B
Marta doesn't question anyone's honesty, expertise, or motives. She could regard James and other advocates of nuclear power as completely trustworthy and still correct this inference. Her response concerns the stage of the technology and its current use, not the credibility of the people discussing it.
- C
James gives reasons for his conclusion: the new extraction method and rhodium's role in catalytic converters. Marta doesn't say those reasons merely assume that nuclear power already contributes to a cleaner environment. She identifies a missing practical step between the invention and the claimed present contribution. That is different from assuming the very conclusion one is trying to prove.
- DCorrect
The overlooked fact is that the technique is still experimental and has not changed the source of rhodium used in manufacturing. James moves from “we can extract it” to “nuclear power is contributing.” Marta points out why that move isn't supported by the current state of production.
Her point leaves open the possibility of a future benefit. It also doesn't establish that nuclear power has no environmental benefits through any other route. It challenges the particular route James offered.
- E
This would compare how believable James's premises are with how believable his conclusion is. Marta makes no such comparison. In fact, she expressly accepts that the technique is effective. Her added fact explains why that accepted premise doesn't establish the conclusion.
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