PrepTest 149, Section 3, Question 18

What we’re looking for

Working the answers

• A
  Correct

  This gets at how long people take the medicines. The toxic effects arise after extended use, so at least some daily users must take the medicines long enough for those effects to become a concern. If no daily user ever took them that long, the described long-term toxicity wouldn't support this recommendation. A doesn't say every user is already suffering side effects; it supplies the needed connection between the risk described and some actual users.

• B

  Losing effectiveness is a reasonable concern, but the herbalist doesn't have to assume that skipping doses makes any medicine work less well. Imagine that occasional breaks reduce toxicity without reducing the desired benefit at all. That would make the recommendation easier to support, and B would be false. B describes a possible cost of the advice, not something required for the argument.

• C

  The recommendation doesn't require some toxicity to remain despite the breaks. Perhaps skipping a day or two eliminates those effects for the relevant medicines. That would be good for the herbalist's proposed solution. We don't need to assume it only partly works.

• D

  The passage says many medicines work best over several months, and the recommendation concerns at least some daily users. It doesn't require every person using any herbal medicine to take it for months. Some medicines could have a different appropriate duration without affecting this argument.

• E

  'Only if' makes reducing long-term toxicity a requirement for any justified break. The herbalist offers that as a reason for some people to skip doses, not the only possible reason anyone could ever have. A different medical reason for a break could exist without undermining the reasoning here.