6. Which of the following is NOT an example of a carbon sink?
a. Deposition of organic matter on the deep
ocean floor
b. Preservation of a tropical rainforest
c. Formation of calcium carbonate shells of
marine crustaceans
d. The vast open ocean
e. Nutrient uptake by the roots of grasses in a
suburban lawn

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.