Animals with a certain behavioral disorder have unusually high level o

An easy B
Aluminum is the cause of the disorder rather than merely an effect of it

I never liked assumptions type of questions, but this one seems to be pretty easy.
I immediately thought about this question:
what if the increased aluminum level is the result of the disorder and not vice-versa?

B is the right assumption!

Cause and effect type question.

A : aluminium level in brain
B : the disorder in brain
Option B shows that A leads to B not B leads to A.

There are so many logical flaws here! There are correlation/causation issues and cause/effect issues. Let's attack them! What is going on here?

We are given a fact: animals with a certain disorder have unusually high levels of aluminum in brain tissue. This is a correlation.

Then we are given another fact: this compound will prevent aluminum from affecting brain tissue. Now watch this subtle jump that the argument is implying here. How do we know that the aluminum affects the brain tissue at all? Maybe it doesn't!

Finally we get the conclusion: Animals can be cured of the disorder with this compound, presumably because the compound prevents aluminum from affecting brain tissue. Here is a cause and effect issue. We have no idea what causes this disorder! It could be that the weather causes this disorder and every animal who has this disorder just so happens to love eating aluminum foil. Who knows?! The main issue here though is that the argument is assuming that the aluminum is the cause and not merely the effect of the disorder.

(A) We don't need to assume that the animals have "invariable" levels of aluminum! Maybe the amount of aluminum changes only very slightly every day. Does that change the argument? Nope.

(C) "Side effects?" We don't care if it does/doesn't have side effects. Maybe it does! So what? Maybe it doesn't! So what? This, like (A), has no bearing on the argument.

(D) This is very similar to (C). This just has no bearing on the argument. Maybe we have to put more of this compound in a dog than a cat but that doesn't really speak to the gap between getting rid of the aluminum and getting rid of the disorder.

(E) This is the most tempting wrong answer. This is tempting because one may think, "well maybe if aluminum is never present then the aluminum is the cause of the disease!" However, this is wrong because of a few reasons: (1) it is simply not necessary! We are talking about "unusually high levels" of aluminum. Maybe everyone has a little bit of aluminum but not everyone has "unusually high" levels of it. (2) it seems to go against the premise. By saying that these animals have "unusually high" levels of aluminum seems to imply that animals have some level of aluminum, just not very "unusually high" levels.

(B) Bingo. Try to negate this and it will destroy the argument. This is the initial gap that I found and it helps to alleviate it beautifully.

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