Self-study
Since 1945 pesticide use in the United States has increased tenfold despite an overall stability in number of acres planted. ██████ ███ ████ ███████ ████ ████ ████ ███████ ███ █████████████ ████████ ████ █████ █████ ██ ████████ ████████
Structure: Surprising Phenomenon
The stimulus points out an unusual phenomenon: since 1945, even though the amount of land used for crops hasn't significantly changed, pesticide use has increased tenfold. In the same time period, crop loss from insects has increased from 7% to 13%.
Analysis: Ways to Reconcile
We need a way to explain how, even though pesticide use has increased by a factor of ten, crop loss from insect damage has nearly doubled. One way to reconcile this tension would be if the reason pesticide use has increased so much is because of a new wave of insect damage sometime after 1945, maybe due to an invasive species or something. In that case, maybe the percentage of crop damage would be even higher than 13% without all the pesticides being used. We can keep speculating, but for RRE questions, it often makes more sense to go straight to the answer choices instead.
11.
Which one of the following, ██ █████ ███████████ ████ ██ ██████████ ███ ███████████ ████████ ██████
a
Extension agents employed ██ █████ ███████████ ██ ██████ ███████ ████ ████████ █████████ █████ ███████ ███████ ██ ██████████ ██████ ██ ████ █████ ████ ████████ █████ █████████ ████
Incorrect. (A) just tells us that agents are now telling farmers to use less pesticide than they used to. This doesn't explain why, even when farmers were apparently engaged in heavy pesticide use after 1945, crop loss from insects still increased.
b
While pesticide-resistant strains ██ ███████ ████ ███████████ ████ █████████ █████ ███ ███████ ████████ █ ██████ ████ ███████ ███ █████████ █████████ ███████ ██████████ ███████████ ██ ███████ ██████████ ████ █████████ ████████ ██ ██████████ ██ █████ ███ ████ █████
Correct. (B) points out an additional factor that helps explain both why farmers are using more pesticides than before, and why crop loss from insects has increased. In the past, crop rotation disrupted insects' food supply, presumably allowing farmers to use less pesticide. The fact that farmers have abandoned crop rotation, along with the fact that insects have developed a resistance to pesticide, helps explain both why farmers are using so much more pesticide (because they can't rely on crop rotation to help deter insects, and because insects are becoming more pesticide-resistant) and why crop loss from insects has also increased (because insects now have a more consistent food supply, and are becoming more resistant to pesticide).
c
Since 1970 the ██████████ ████ ██████ ██ ██████ ████ █████████ ████ ████████ ██ ███████████ █████████ ████ ███ ███████ █████████ ███████ ███████ ███ ████ █ █████████████ ██████ ██ ███ ████ ██ ███████ ███ ██ █████ ████ ████ ███ ████ ███████ ████████████ ███████
Incorrect. Knowing that the pesticides in use after 1970 have been less damaging to people and to fish is irrelevant. We're interested in the pesticides' effect on insects, and since (C) just tells us that these pesticides have the same effect on insects as the ones used before 1970, we still have no idea why farmers have had to use so much more pesticide, and why insect damage has nevertheless nearly doubled.
d
Because farmers’ decisions █████ ███ ████ ████ ██ █████ ███ ████████ ██ █████ ████████████ █████ ████ ██████ ██ ███████ █████ ███ ██████ ██ █████████ ████ █████ ████ ███████ ██ ████ ██ ████████ ████ ███████
Incorrect. (D) says that the amount of pesticide farmers apply depends partly on expected crop prices. This might help explain the rise in pesticide use after 1945 if we knew that crop prices had also increased tenfold since 1945. But we don't know that — and even if we did, (D) still wouldn't explain why, despite the rise in pesticide use, crop loss from insects has also increased.
e
Although some pesticides ███ ██ ███████ ████ ██████████ ███████ ████████ ██████ ███ █████ ██ ████ ███ ██████ ███████ ██ ███████ ███ █████████ ████ █████ ██ ███████ █████ ██████████ ██████████ ████ ██████ ██ ██████ ████
Incorrect. (E) is talking about the effect of pesticides on consumers, which is irrelevant to reconciling the tension in the argument.