Caffeine can kill or inhibit

Answer choices

1. A

   Out of Scope: commercial insecticides0% picked this

   caffeine-producing plants are an important raw material in the manufacture of

   The author never mentions or implies anything about how commercial insecticides work. Just because she believes that plants evolved caffeine as a defense against insects doesn't mean she assumes that human attempts to thwart insects also involve caffeine.

   0%
2. B

   Too Strong: roughly equal19% picked this

   caffeine is stored in leaves and other parts of caffeine-producing plants in concentrations roughly equal to the caffeine concentration of the preparation

   There's no reason the author needs to assume that the concentration of coffee in leaves is roughly equal to the caffeine concentration of the mix fed to the hornworm. Whether there's more caffeine in leaves or more caffeine in the mix wouldn't make any difference to the argument. The first sentence establishes that caffeine has a deleterious effect on many insects. The experiment might have had a much more concentrated dose than leaves do, but why would that mess up the argument?

   19%
3. C

   Too Strong: wherever Reversal, if anything11% picked this

   caffeine-producing plants grow wherever insect larvae pose a major threat to indigenous plants or once posed a major threat to

   The author doesn't have to assume that in every single place where insect larvae threaten local plants or ancestors of those plants, that caffeine-producing plants grow. If there's some island where insect larvae pose a threat to local plants, and there's no caffeine-producing plants to be found on that island, would that badly weaken this argument? No, it would have no effect. It's not like the author was ever saying that the only way plants can defend themselves against insect larvae is to evolve caffeine. This answer would be closer to being apt if it were reversed. Since the author believes that caffeine is an evolutionary response to these insects, she would be closer to believing that "wherever we find indigenous caffeine-producing plants, we'll find that there are or were insect larvae posing a threat to those plants".

   11%
4. D

   Out of Scope: tobacco plant9% picked this

   the tobacco plant is among the plant species that produce caffeine for

   We might speculate that the tobacco hornworm is named that because it eats tobacco plants (and thus that tobacco plants might have evolved caffeine as a defense), but none of that needs to be true. If the tobacco plant isn't a species that produces caffeine, that wouldn't hurt the argument.

   9%
5. E

   Correct61% picked this

   caffeine-producing plants or their ancestors have at some time been subject to being fed upon by

   Why this is right

   This has lovably soft language "have at some time", and it's basically the reversed version of (C). In order to believe that caffeine-producing plants evolved caffeine as a defense mechanism, you have to believe that there was something in the environment of these plants that threatened the plants and that would be deterred by caffeine. i.e., in order to believe that the giraffe evolved its long neck in order to better reach food that was high up, you have to assume that within the giraffe's habitat, there were food sources that were too hard to reach without a long neck. If we negate this answer, it's saying, "Caffeine-producing plants, as well as their ancestors, have never been fed upon by creatures sensitive to caffeine." That would badly weaken the argument. How could caffeine possibly have evolved as a defense mechanism if nothing that feeds/fed on these plants is deterred by caffeine?

   Skill tested: Necessary Assumption · how this choice captures the argument's function is the move to repeat next time.

   61%