Which of the following scenarios is representative of commensalism?
a.
tapeworms living in a mammal’s intestinal tract
b.
bees pollinating flowers
c.
birds following grazing animals who stir up insects
d.
clown fish living among sea anemones

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.