« on: October 01, 2007, 04:22:47 PM »
Agreed. While it may seem that E strengthens the conclusion, the fact is that it doesn't really relate to anything in the stimulus. The reason that A is right is that it directly addresses the reasoning that led to the conclusion. Essentially, the conclusion is saying that the fact that less were seen in 1989 is due completely to the dryness. While E certainly eliminates an alternate explanation, it doesn't strengthen the reasoning in the question. What A does is connect the premise (dry = less active, i.e. less moving) to the conclusion (dry = less seen) by saying that less active = less seen. By doing that, it does exactly what Beantown said, which is get rid of the missing link found in the reasoning.
Strengthen answers will essentially always work by addressing a possible flaw in the reasoning itself, not necessarily by eliminating alternate explanations.