Which of the following would serve as an example of "concomitant structural features" that might disadvantage a snail of the rarer form? A. A shell and body that are an exact mirror image of a snail of the commoner form B. A smaller population of the snails of the rarer form C. A chip or fracture in the shell caused by an object falling on it D. A pattern on the shell that better camouflages it E. A smaller shell opening that restricts mobility and ingestion relative to that of a snail of the commoner form