PrepTest 141, Section 2, Question 20
The advent of chemical fertilizers led the farmers(57 more words not shown)
The argument relies on the(2 more words not shown)
- Amost, if not(16 more words not shown)
- Bapplying chemical fertilizers(13 more words not shown)
- Cthe most important(12 more words not shown)
- Dchemical fertilizers themselves(11 more words not shown)
- Emany, if not(18 more words not shown)
Reading the argument
Why can't the farmers do both?
The fertilizers led them to stop periodically growing crops such as alfalfa to rejuvenate the soil. We can accept that this change left the soil structure in poor condition. But the conclusion says they need to stop using chemical fertilizers to improve it. What if they keep the fertilizers and start growing those restorative crops again?
That's the distinction to watch: the fertilizers prompted the farmers to abandon a useful practice. That doesn't automatically mean the fertilizers themselves prevent good soil structure. We need a reason why the useful practice can't simply be restored alongside their use.
What we’re looking for
The question asks for an assumption the argument relies on. Look for a connection making abandonment of fertilizers necessary for the proposed improvement. We don't need a promise that quitting fertilizers, by itself, guarantees the whole problem will be solved.
Working the answers
- A
This promises what farmers will do after they quit fertilizers. But a required step isn't necessarily a step that guarantees the result. Imagine a rule requiring you to be an astronaut to travel to Mars. Becoming an astronaut wouldn't guarantee that you ever get there. Likewise, saying farmers need to quit fertilizers doesn't promise that most will then grow alfalfa. Alfalfa is also only one example of a green-manure crop.
- B
The argument doesn't need fertilizers to provide no growth benefit to these crops. They could help the crops grow while their availability still discourages farmers from planting them. Whether the crops benefit when fertilized doesn't settle the farmers' willingness to restore the practice.
- C
We aren't ranking all the factors that affect overall soil quality. The evidence and conclusion both concern soil structure. Improving that particular feature doesn't require it to be the most important aspect of soil quality.
- D
This is tempting: if fertilizers directly damage soil structure, stopping them could matter. But direct damage isn't required by the argument. The problem could be entirely indirect: farmers keep using fertilizers, so they refuse to grow the restorative crops. The argument can depend on that behavior without depending on the chemicals themselves destroying soil structure.
- ECorrect
This connects continuing fertilizer use with the farmers' refusal to grow green-manure crops. For many farmers, restoring that practice requires abandoning the fertilizers. It blocks the proposed “Why not do both?” response for those farmers.
Don't reject “many” because it isn't “all.” The answer supplies a weaker commitment than a claim about every farmer. Nor must this assumption prove that quitting fertilizers solves every soil problem. We're identifying something the argument needs, not demanding a complete guarantee of success.
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