Correct me if I am wrong in my explanation.
*The kind of question this is:* Weaken
*CTX:* Local agricultural official gave fruit growers of District 10 a new pesticide that they applied for three years to their pear orchards in place of the pesticides they had used before.
*Premise(s):* during the three years, the proportion of pears lost to insects was significantly less than it had been during the previous three years period.
*Conclusion:* based on the results, the official concluded that the new pesticide was more effective than the old pesticide, at least in the short term. In limiting the loss of certain fruit to insects.
*What I am looking for:* Just looking for answer choices that weaken the argument. Maybe an alternative explanation as to why the pears lost to insects were significantly less than it had been during the previous three years period.
*Answer A:* Yes, this is the right answer. This is irrelevant and does not weaken the argument. There were less fruit being produced because the number of mature trees has declined of the past 8 years. Who cares. The argument is talking about the “proportion of pears lost to insects.” So, it doesn’t matter how many pears we started with, it’s how many of those that were lost to insects with the new pesticide.
*Answer B:* Not the right answer. This weakens the argument. Insect abatement programs were used in the last 5 years, and were successful. That explains why the pears lost to insects were significantly less than it had been during the previous three years period.
*Answer C:* Not the right answer. Over the past 5 years, the birds that prey on the insects that feed on the pears have spent more time in the district 10 region. Weakens.
*Answer
* Not the right answer. Insects in district 10 that infest pear trees are water breeders, and access to water for them is shrinking. This means the insects did not get to the pear trees. Weakens.
*Answer E:* Not the right answer. It is saying the old pesticide is still in effect after it has stopped being used, so it may not be the new pesticide that is credited with eliminating many pear eating insects. Weakens.