in this laboratory experiment, you will write a narrative history of a rock section found in the grand canyon. you will describe and explain the events starting with the vishnu schist forming and ending with the unconformity above the redwall limestone in the mississippian. your description should include environmental changes.

1. interpret the bottom half of the cross section below. start with the vishnu schist and end with the redwall limestone.

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.