How does the desirable traits in natural selection are passed along

Isolated volcanic peaks on the ocean floor are

Which of the following factors would not contribute to allopatric speciation? a) a population becomes geographically isolated from the parent population.b) the separated population is small, and genetic drift occurs.c) the isolated population is exposed to different selection pressures than the ancestral population.d) different mutations begin to distinguish the gene pools of the separated populations.e) gene flow between the two populations is extensive.

Some substances but not other can cross the (blank) membrane of a cell