rafaelitorafaelito Alum Member
edited May 2017 in Logical Reasoning 1063 karma

I'm adding my explanation to this question since it doesn't currently exist on 7sage. Feel free to critique my reasoning.

This is a necessary assumption question. We know this because the question stem says the argument above makes which one of the following assumptions? The correct AC must be an assumption we know the argument makes. Therefore, it is a necessary assumption.

P: R bacteria provide nitrogen to bean plants and other legumes. Nitrogen is an essential plant nutrient. Wheat must normally be supplied nitrogen by nitrogen fertilizer.
C: If technology produces wheat strains that will host R bacteria, the need for fertilizers will be reduced.
Flaw: I originally thought but what if nitrogen is not the only essential plant nutrient for plants to grow? Might the need for fertilizer remain? B plays on this erroneous understanding. This isn't the actual flaw.

A. 'should' is irrelevant. This is not about what should happen it's about what is/will happen.

B. This was temping and it the trap answer choice. The conclusion says the need for artificial fertilizers will be reduced if biotech succeeds in producing wheat strains who host R bacteria. What about other reasons growers need to add fertilizer? Can we conclude from no longer needing nitrogen that fertilizer demand in general will be reduced? Even if nitrogen only comprises a small subset of all fertilizer use, if we eliminate the nitrogen need, then yes, the fertilizer demand will be reduced. This is true even if nitrogen is not the only soil nutrient that must be supplied. The key word to not falling for this trap answer choice is "reduced." Perhaps I was temped because I was thinking "eliminated." If the conclusion said the demand would be eliminated then yes nitrogen would have to be the only reason growers use fertilizer.

C. This is not necessary. It talks about other grasses but even if it didn't, even if there are strains of wheat that do have R naturally, we know there are some that aren't. That's what the whole argument is about so this is irrelevant.

D. Similar reasoning to C. We don't need legumes to be the only crops that produce nitrogen. We know some wheats don't and we know there is an existing need for nitrogen based fertilizer. The argument is simply saying the need will go down if wheat is modified to host R bacteria.

E. This is absolutely necessary. If the R bacteria did not produce nitrogen in the wheat roots then it wouldn't reduce the need for artificial fertilizer. This is the true flaw. Just because the plant will host the bacteria doesn't mean that it will necessarily have the desired effect.

Sign In or Register to comment.