Help please

While it is true that the manufacturers of melatonin might be biased about information relating to their product, that is not /why/ the pharmacist’s argument is flawed. That is, it is not as if the pharmacist’s argument is: manufacturers of melatonin told me X, therefore it must be true! That would be an example of reliance on the opinion of individuals who are likely to be biased. Instead, the flaw is related to the fact that the study was about people aged 65-81 AND suffering from insomnia, and the effect of ingesting melatonin for that group. The claim by manufacturers on the other hand was about the causal relationship between aging and producing melatonin — the manufacturers are assuming that it is age driving the melatonin production, when the sample was about a certain age group AND insomniacs. Therefore, the sample may have been unrepresentative, and that answer is flawed — and therefore answer E is correct. I hope this helps! Please let us know if you have further questions.

Why is D not the correct answer?

@GLEE, Answer choice D is incorrect because it inaccurately describes the flaw in the argument. D says that the argument confuses an effect of a phenomenon with its cause. This sounds really high-level and abstract, so let's figured out what this actually means and why it makes no sense. The argument's conclusion is that an increase in age causes a reduction in the pineal gland's production of melatonin. The purported cause is aging and the purported effect is the pineal gland's production of melatonin. increased age - -causes - -pineal gland to make less melatonin D says that the argument is confusing an effect of a phenomenon with its cause. In order for D to be true, then the argument would have had to say something about the effect of the phenomenon (pineal gland making less melatonin) actually being the cause and the cause (aging) actually being the effect. So, if D were true, we would also have to see somewhere in the argument where the pharmacist was saying that pineal gland making less melatonin - -causes - -aging This isn't found anywhere in the argument, so we can eliminate this answer. Does this make sense? Let us know if you have more questions!