The second paragraph of the passage is primarily concerned with offering possible reasons why A. it is unlikely that evolutionary mechanisms could discriminate against sinistral snails B. sinistrality is relatively uncommon among snail species C. dextral and sinistral populations of a snail species tend to intermingle D. a theory based on a developmental mechanism inadequately accounts for the predominance of dextrality across snail species E. dextral snails breed more readily than sinistral snails, even within predominantly sinistral populations