answer choice (A)

Hi @Shirnel, Thanks for the question! So we’re told in this passage that there are animals with a certain behavioral disorder that have an unusually high level of aluminum in their brain tissue. Then we’re told about something that’ll bind to aluminum and prevent it from affecting the brain tissue, and this is supposed to be able to cure animals of the disorder. So now we’re asked to determine assumptions that the argument is based on. Clearly, doing a bit of pre phrasing, one of the assumptions is that the aluminum somehow causes the disorder and has some effect. Otherwise, if it didn’t, it wouldn’t matter if we could bind the aluminum and make it ineffective, since it didn’t contribute in the first place. That’s a pretty good one to start with, and we can now move into the answer choices. Now let’s take a look at (A). It tells us that animals with the disorder have unusually high but invariable levels of aluminum in their brain tissue. Is this an assumption the argument is based on? Well, let’s try negating it and find it. Animals with the disorder don’t have unusually high but invariable levels of aluminum in their brain tissue. Seems like it still works with the premise. One easy way of negating this: maybe animals with the disorder have unusually high but variable levels of aluminum. So maybe the normal amount of aluminum is 5, but these animals have 23, 42, 21, etc. These are variable levels (they change) and still high, and is still consistent with the passage, and so we can eliminate (A) as not being an assumption that the argument requires. (B), on the other hand, matches up with the pre phrase, since if aluminum is an effect and not a cause, then there’s no point in taking it out like I said earlier. And so (B) is an assumption that the argument is based on. Hope this helps! Feel free to ask any other questions that you might have.

(A) is pretty much a restatement of the first sentence of the passage. When we see this, can we always eliminate it from being the answer on strengthen questions?