Question ID:PT5 S3 Q5 Passage:Animals with a certain behavioral disorder have unusually high levels of aluminum in their brain tissue. Since a silicon-based compound binds to aluminum and prevents it from affecting the brain tissue, animals can be cured of the disorder by being treated with the compound. Stem:The argument is based on which one of the following assumptions? Correct Answer Choice:BChoice A:Animals with the disorder have unusually high but invariable levels of aluminum in their brain tissue. Choice B:Aluminum is the cause of the disorder rather than merely an effect of it. Choice C:Introducing the compound into the brain tissue has no side effects. Choice D:The amount of the compound needed to neutralize the aluminum in an animal’s brain tissue varies depending upon the species. Choice E:Aluminum is never present in normal brain tissue.