Explain why a circulatory system is important in meet
the needs of all cells throughout an animal's body.

The model illustrates a process by which a substance is taken up by a cell

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 are the pros and cons of quadrat sampling?