Most plants have developed chemical defenses against parasites. The average plant contains about 40 natural pesticide...

James on August 4, 2020


Can someone explain why D is wrong and why E is correct? thank you.

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Shunhe on August 5, 2020


Thanks for the question! So remember, this is a weaken except question, which means the correct answer choice will either strengthen the argument or won’t affect it (if it’s just irrelevant, for example).

Let’s walk through the argument quickly: most plants have chemical defenses against parasites and basically make natural pesticides. But humans eat these and are fine. So adding on synthetic pesticides doesn’t pose much more of a threat. This last sentence is going to be the conclusion that we’re trying to not weaken.

So let’s take a look at (E), which tells us that the synthetic pesticides sprayed on crop plants by humans usually have chemical structures similar to those of the natural pesticides produced by the plants. Well, if that’s true, we might think that the natural pesticides and chemical pesticides act in similar ways. And if we can eat the natural pesticides, then we might be able to eat the synthetic ones too, so they have similar chemical structures. Since (E) tells us a way in which the two are similar, thus making it more likely their effects will be similar, it actually likely strengthens the argument (and certainly doesn’t weaken it) and so is the correct answer choice.

(D), on the other hand, tells us that natural pesticides only hurt some parasites, whereas synthetic pesticides are harmful to a lot of different organisms. Well, if that’s true, then synthetic pesticides might hurt humans too! And then that would weaken the argument that the additional threat by posing synthetic pesticides is minimal. So (D) weakens and is out.

Hope this helps! Feel free to ask any other questions that you might have.

Trevor on August 19, 2020

How does A weaken this argument?? It seems like it strengthens the argument or does nothing?