#11 - Peter: Because the leaves of mildly drought-stressed

[Administrator]

Complete Question Explanation

Strengthen. The correct answer choice is (C)

As with all Strengthen questions, begin by isolating the conclusion of the argument: since insects prefer to feed on the leaves of abundantly watered plants, Peter concludes that farmers should underwater their crops. To quickly prephrase an answer that strengthens this argument, you should examine the stimulus for any gaps between the premise(s) and the conclusion. The correct answer to a Strengthen question will close these gaps. For instance, even though drought-stressed plants are less likely to sustain insect damage, it is entirely plausible that the risk of damage caused by drought can outweigh the risk presented by insects. Answer choice (C) eliminates this possibility and thus strengthens the implicit proposition that insects present a greater threat to plants than drought stress.

Answer choice (A): The fact that the leaves of some crop plants absorb more water than others does not strengthen Peter’s recommendation. If anything, it shows that his advice may not apply uniformly to all crop plants. This answer choice is incorrect.

Answer choice (B): The fact that abundantly watered crops outnumber the mildly drought-stressed ones neither strengthens nor weakens Peter’s proposition that farmers would be better off if they watered their crops less. This answer choice is incorrect.

Answer choice (C): This is the correct answer choice. See discussion above.

Answer choice (D): If some of the water crops receive is beyond the farmers’ control, Peter’s recommendation may not always be entirely effective in preventing the abundant watering of plants. On the other hand, farmers have complete control over how much additional water their crops receive, and we can assume that this amount will vary depending on how much rain the crops receive. At best, this answer choice has no effect on Peter’s conclusion and is therefore incorrect.

Answer choice (E): If soybean growers adopted Peter’s recommendation, their plants would have a heightened exposure to the harmful effects of Mexican bean beetles. Because this answer choice suggests that some insects prefer the leaves of drought-stressed plants over those of abundantly watered plants, it presents a counterexample to Peter’s conclusion and thus weakens his argument.

[Coleman]

Hi,

I got this strengthen question right, but not feel entirely confident about how did reach the correct answer. What I'm confused about is Peter's conclusion. He states, "Therefore, to minimize crop damage, farmers should water crops only just enough to ensure that there is no substantial threat, FROM A LACK OF WATER to either the growth or the yield of the crops." Since abundantly-watered plants are more vulnerable to insects than mildly drought-stressed plants, he encourages farmers to UNDERWATER to plants.
However, it also sounds like farmers have to pull more water to the mildly drought-stressed plants because they might be stricken from a lack of water that would decrease the growth or yield of their crops. Thus, Peter's conclusion will be not just underwater the plants, but rather farmers have to aim the exactly right level of watering that avoids both consequences. (overwater-insects/ underwater-growth&yield) I thought this may include pouring more water to the mildly drought plants.

Answer choice C states "Insect damage presents a greater threat to crop plants than does mild drought stress."
This answer choice will be valid as a strengthening answer only when we isolate Peter's argument as underwatering part. I don't understand why we should more focus on the underwatering element of Peter's conclusion when he especially addresses the issue that arose from a lack of water. Doesn't this argument have dual purposes? such as we have to give plants less water but also more water, so we could be free from both undesirable results?

Thanks in advance!

[Adam Tyson]

I'm not seeing what you're seeing there, Coleman. The author is not suggesting that farmers bring more water to the plants, but that they bring less. This isn't about how to handle plants that are already stressed by drought, but about how to treat plants generally to create the best conditions for them. Farmers should limit watering just enough to cause a little bit of stress, like would happen in a drought, to toughen them up and get protection from insects, but not so much that they harm the plants from lack of water. In short, they should dial back the watering just enough to hit that sweet spot.

This argument gets help from answer C by eliminating the possibility that reduced watering might be worse for the plants than the insect damage would have been. What if, for example, a little bit of drought stress causes plants to have great difficulty extracting nutrients from the soil, or they become less efficient at photosynthesis? What if they become more vulnerable to other pests, like rabbits or deer? Those aren't threats from lack of water, but from other potential sources. Answer C lets us know that those problems, if they exist, are not as bad as the insect damage that we are trying to prevent, and that helps support the recommendation. The author must have assumed that answer C was true, and so saying that assumption out loud helps to support the argument.