Genetic variation by itself will not result in natural selection unless it exerts some impact on organism survival and reproduction.
By producing progeny cells that include plasma cells and memory cells
Answer:
Two groups of proteins, called cyclins and cyclin-dependent kinases (Cdks), are responsible for the progress of the cell through the various checkpoints. Cyclins regulate the cell cycle only when they are tightly bound to Cdks.
Explanation:
A)Demographic; because the census studies things such as births,death, and even disease which show changes in human population