Question ID:PT78 S1 Q9 Passage:In a recent field study of prairie plants, the more plant species a prairie plot had, the more vigorously the plants grew and the better the soil retained nutrients. Thus, having more plant species improves a prairie's ability to support plant life. Stem:The argument is most vulnerable to criticism on the grounds that it Correct Answer Choice:AChoice A:infers of two correlated phenomena, X and Y, that X causes Y without considering whether Y causes X Choice B:fails to describe the mechanism by which productivity is supposedly increased Choice C:takes for granted that the characteristics of one prairie plot could reveal something about the characteristics of other prairie plots Choice D:bases a general conclusion on data that is likely to be unrepresentative Choice E:takes an increase in number to indicate an increase in proportion