Why would it be beneficial for cells to wait until a critical population density is reached before expressing certain genes

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.

What part of the brain is highlighted in the diagram below?

Most animal cells membranes have proteins that pump ions out of the cell and potassium ions into the cell