Marine: explain how deep water currents affect the number of organisms found in the area by circulating nutrients.

How does natural selection change thephenotypes within a population over time?

1. variations in a population of moths allow for some of its members to be able to adapt to environmental changes. the better adapted of the moths will be able to survive the change and thus prevail as the “fittest” of the species. (a) describe three mechanisms in which variation can occur within a species population. (b) explain which mechanism or mechanisms would be responsible for the survival of a population of peppered moths better than white moths in an environment affected by industrial soot. justify your answer.

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?