GRE Reading Comprehension: JiJing 352-GRE阅读机经352篇 - 5PVC75HSQ057NG55J

In describing the "evolutionary mechanism", the author mentions which of the following? A. The favorable conditions for nurturing new offspring B. The variable environmental conditions that affect survival of adult snails C. The availability of potential mates for breeding D. The structural identity of offspring to parents of the same hand E. The frequency of unions between snails of different species