Humans widely use pesticides on plants as a means to control insect and plant pests. However, pesticides are not selective in what they kill, so they often kill beneficial insect and plant species as well. This unintentional consequence favors plant and insect species that are pesticide resistant. This scenario is an example of

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.