Several years ago, as a measure

Answer choices

1. A

   Correct71% picked this

   A strain of gypsy moth whose caterpillars are unaffected by the fungus has increased its share of the

   Why this is right

   This gives us a classic "No Cause, No Effect" plausibility strengthener (the most common form of correct answer when we Strengthen an Explain Curious Fact argument). The author thought that the fungus was causing a decrease in gypsy moths. This answer shows that where there is no danger of the fungus (a strain that's unaffected by it), there is no decrease in gypsy moths (in fact, there's an increase!) To put it another way, "You can tell that the fungus is effective, because the only gypsy moths that are doing okay are the ones that have an immunity to the fungus."

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

   71%
2. B

   Unclear Impact16% picked this

   The fungus that was introduced to control the gypsy moth population is poisonous to few insect species other

   It doesn't really matter whether the fungus is a surgically specific killer of moth but not other insects, or whether the fungus is just a big ol' bomb that wipes out lots of insects too. The conclusion is just about whether the fungus is killing the moths, which could happen or not happen in either of those scenarios. We don't know whether other insects are / aren't also in decline. So we have no way to judge whether the actual decreases in insects are moth-specific or more generalized. If we knew that few other insect species in the moth's habitat have been experiencing a decrease since the fungus was introduced, then this answer would strengthen somewhat.

   16%
3. C

   Opposite (if anything)7% picked this

   An increase in numbers of both gypsy moth caterpillars and gypsy moth adults followed a drop in the number of some of the

   This answer is talking about how changes in predator population seem to influence changes in the moth population. If anything, that's giving us fodder for an alternate explanation of why the moths are in decline (maybe their predators are on the rise!).

   7%
4. D

   Opposite Impact2% picked this

   In the past several years, air pollution and acid rain have been responsible for a substantial decline

   This weakens because it suggests another potential cause for the decline: reduced oak populations due to air pollution and acid rain. If there are fewer oak leaves due to these factors, caterpillars might starve, offering another explanation and thus weakening the argument.

   2%
5. E

   Opposite Impact4% picked this

   The current decline in the gypsy moth population in forests where the fungus was introduced is no greater than a decline that

   This weakens the argument, because it hurts the plausibility that the fungus is the cause of the decrease in moths, because the decrease in moths is occurring to the same degree in places where there isn't fungus. (a classic Effect w/o Cause weakener)

   4%