Logical Reasoning

PT4 · S1 · Q10 Rhizobium bacteria living in the

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Rhizobium bacteria living in the roots of bean plants or other legumes produce fixed nitrogen, which is one of the essential plant nutrients and which for nonlegume crops, such as wheat, normally must be supplied by applications of nitrogen-based fertilizer.

Conclusion (So)

If biotechnology succeeds in producing wheat strains whose roots will play host to Rhizobium bacteria, the need for artificial fertilizers will be reduced.

Evidence

Rhizobium bacteria living in the roots of bean plants or other legumes produce fixed nitrogen, which is one of the essential plant nutrients.

For nonlegume crops like wheat, fixed nitrogen normally must be supplied by applications of nitrogen-based fertilizer.

Evaluate

Not the funnest read. First, let's start with the conditional conclusion. We always play along with the trigger. We have to evaluate the argument within the hypothetical world where the trigger is true, so you just sort of mentally stipulate:

This takes on a Plan / Goal vibe from there.

PLAN: Wheat strains have roots that will host Rhizo >> Rhizo will produce fixed nitrogen.

GOAL: don't need to use as much nitrogen-based fertilizer on the wheat crops.

The author has to assume that

But maybe the nitrogen that Rhizo can produce isn't in the right form to be used by wheat crops?

Maybe the fertilizer does other stuff besides just supply nitrogen, so even if the Rhizo is supplying some nitrogen, we still need to use just as much fertilizer for the sake of the other stuff?

Maybe having Rhizo on the roots backfires in some way, creates some sort of change to the growth of the wheat crops where you would need additional fertilizer to counteract that change?

Goal

This is probably likely to be a Defender answer, ruling out a potential obstacle to the plan working as intended.

10.

The argument above makes which one of the following assumptions?

Biotechnology should be directed toward
Bad Assumption
When we're being asked which answer can be derived from the text (as we are on Necessary Assumption and Must Be True), it's super dangerous to pick an answer using "should" language if the paragraph never used that kind of language. The argument simply describes what would happen in a hypothetical world. It never involves any opinions about what should happen.
2% picked this
Fixed nitrogen is currently the
Bad Assumption
This is a famous style of trap answer on NA / MBT: treating "the only thing mentioned" as though it's "the only thing". The only nutrient we mentioned that we use fertilizer for is nitrogen, but that doesn't mean it's the only nutrient we use fertilizer for. If we negate this and say that there are other nutrients that also must be supplied by artificial fertilizer, it doesn't weaken the argument. If the conclusion said "the need for artificial fertilizers will be eliminated", this would work. But the conclusion is only claiming that it will be reduced, because we'll no longer need as much fertilizer to supply nitrogen.
16% picked this
There are no naturally occurring
Bad Assumption
The conclusion is only about wheat strains, so it's already dubious for this answer to be stretching to talking about other grasses. We might be thinking, "If we negate this, it's saying that there are already wheat grasses that have Rhizo living in their roots, so even if biotech produces a strain, it won't change anything." However, we know that wheat normally must be supplied by applications of nitrogen-based fertilizer, so it's clearly not currently the case that wheat crops host Rhizo and get their nitrogen from there. And the negation of this wouldn't tell us that there are currently wheat strains that host Rhizo. It would only say, "there is at least one strain of wheat or some other grass that has Rhizo in its roots".
10% picked this
Legumes are currently the only
Bad Assumption
This is a famous style of trap answer on NA / MBT: treating "the only thing mentioned" as though it's "the only thing". Legumes are the only crop mentioned that produces their own supply of fixed nitrogen, but that doesn't mean the author thinks they are the only crop that does so. If we negate this and say that there are other crops that also produce their own nitrogen, it's irrelevant to the conclusion. The conclusion is about wheat, which doesn't produce enough nitrogen on its own (it needs applications of nitrogen fertilizer).
1% picked this
Correct
Rhizobium bacteria living in the
Why this is right
This is just a basic bit of needed Plausibility for this plan to work. The plan is for wheat crops to host Rhizo, which will then produce fixed nitrogen that can be used by the wheat crops, thereby lessening the need for us to apply nitrogen-laced fertilizers on the wheat crops. Well, if we negate this and say "Rhizo living in the roots of wheat crops won't produce fixed nitrogen", then it totally derails the whole plan! We might realize at this point (if we didn't think of it while evaluating the argument), that this Plan was Assuming a Similarity. It was assuming that "if Rhizo produces nitrogen when it lives in the roots of beans and other legumes, then it will also produce nitrogen if it lives in the roots of wheat."
Skill tested: Necessary Assumption · how this choice captures the argument's function is the move to repeat next time.
71% picked this

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