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PrepTest 73, Logical Reasoning 2, Question 26


Question 26 wants an assumption that the argument requires, which means that it is a necessary assumption question. These questions ask us to identify an assumption that the argument requires. Something that, if it's not true, will ruin the argument. There can be a lot of necessary assumptions in an argument, but of course, only one will show up in the answer choices.

In order to find the assumptions, you have to understand the argument, which means breaking it down into its conclusion and its evidence. The conclusion of this argument comes at the end. Using such genetically engineered crops more widely is likely to help wildlife populations recover. Now the rest of the information is evidence of some kind.

The first sentence tells us something about crops that are genetically engineered to produce toxins that enable them to resist insect pests. So those genetically engineered crops don't need to be sprayed with insecticides. And we also know another piece of evidence marked with the evidence keyword since excessive spraying and insecticides has harmed wildlife populations near the crop lands.

So we have some new crops, they're genetically engineered to not require pesticides. Excessive spraying of pesticides has really hurt the wildlife near our crops. So if we were to switch over to these new genetically engineered crops, that's probably gonna help the wildlife recover. This argument has a pretty common pattern to its assumptions because it is a net benefit calculation.

They give us something that's bad and something that's good and then they conclude that switching from the bad thing to the good thing would be good overall, a new thing is going to help the problems caused by the bad thing. The bad thing being pesticides, the good thing being these new genetically engineered crops. This requires assuming that there is no unstated harm or benefit that could swing our understanding.

In other words, there's nothing good about the insecticides or bad about the genetic engineering, that would mean that switching wouldn't be a good idea. So that's what our assumption's gonna be. On balance, the genetically engineered crops are better than the pesticides. All we know is those crops don't need to be sprayed with insecticides. So we need them to be better overall in order for them to be able to fix the damage.

So answer choice A, well, that's exactly what we just said. So use of these crops, the genetically engineered ones, will cause less harm than the ones sprayed with insecticides. That's what we wanted. We wanted genetically engineered crops to be better than insecticides sprayed crops, and answer choice A says that.

So that is our answer. What's wrong with the others? B would actually hurt the argument. If all the wildlife needs to recover as a slight reduction pesticides, then we have no reason to believe that switching until you genetically engineered crops will be likely to fix things.

Their only advantage is at least according to the evidence that they don't require pesticides. Now answer choice C, it brings up crops that have never been sprayed with insecticides, or would never be sprayed with insecticide. The damage the argument's trying to fix is damage from excessive spraying of pesticides.

So we don't need to eliminate pesticides entirely, just to eliminate the excessive use of them. So C is not the answer. D, D brings up cost. And cost is entirely outside the scope of this argument. The farmer who's giving this argument is only trying to prove what's going to help the wildlife recover.

They're not taking a stand on whether helping wildlife recover would be financially beneficial or not. So D, not our answer, and then answer choice E, answer choice E goes too far. For our argument to work, we need to believe that genetically engineered crops are better than pesticides. We don't need to believe that the only advantage that they have is that they avoid pesticides.

In fact, if they had other advantages, that would be good for the argument. So this answer is adding a restriction that the argument doesn't need. So it's not the answer to a necessary assumption question, the answer was answer choice A.

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