Bunuel
Seedling growth inhibitors are herbicides that interfere with new plant growth. Plants absorb seedling growth inhibitors from germination until the seedling emerges from the soil, after which point the seedling growth inhibitors can no longer harm the plant. Among the types of seedling growth inhibitor are root inhibitors, which prevent cell division, thereby inhibiting shoot elongation and lateral root formation. Root inhibitors are absorbed through the developing roots and shoots which receive the bulk of the damage to the plant.
Which of the following, if true, would most strongly support the position that it is inadvisable to protect corn crops by using root inhibitors on weeds vulnerable to the herbicide?
A The seedlings of corn plants generally appear above the soil before the shoots of the weeds common in corn crops.
B. Most weeds are susceptible to some type of herbicide.
C. Not all weeds can be eradicated by root inhibitors.
D. The root inhibitors can damage the roots and shoots of plants beneficial to corn plants as well as any unwanted plants.
E. Although botanists have developed root inhibitors in the lab and tested them in the field, there is no major production facility producing them.
Kaplan Official Explanation:
Identify the Question Type:The phrase "would most strongly support" indicates this is a Strengthen question. Note, though, that the conclusion is actually stated in the question stem itself.
Untangle the Stimulus:The stimulus states that seedling growth inhibitors are herbicides that interfere with new plant growth. Root inhibitors, a type of seedling growth inhibitor, prevent shoot elongation and lateral root formation.
Predict the Answer:The conclusion (from the question stem) is that the root inhibitors should not be used to prevent weeds around corn crops. Using the inhibitors should provide corn from protection against harmful weeds. To argue against such protection, there must be some overriding disadvantage -- an unmentioned side effect that outweighs the benefit. The correct answer will verify this assumption, validating the idea that root inhibitors should not be used to protect corn crops from weeds.
Evaluate the Answer Choices:(D) is correct, because it gives a reason why, despite the benefits of root inhibitors, it's not a great idea to use them to protect corn crops. Not only do they kill the weeds, but they also kill the plants that are beneficial to corn plants.
(A) is a 180. It weakens the argument by suggesting that the herbicide can used on the weeds at a point when the corn plants themselves will not be harmed by the herbicide.
(B) is incorrect since the question specifically refers to weeds known to be vulnerable to the root inhibitors, so this doesn't suggest a reason why root inhibitors shouldn’t be used to protect corn crops.
(C) is irrelevant, because the question specifically refers to weeds known to be vulnerable to the root inhibitors.
(E) focuses on the lack of major production facilities for the root inhibitors. This has nothing to do with the connection between how root inhibitors work and the claim that they shouldn't be used to protect corn crops.
TAKEAWAY: When the argument advises against a certain action, and the evidence states reasons in favor of that action, a strengthener will suggest why, even though there are reasons in favor of it, the action should not be taken.