Will make !

the cell cycle is regulated by both external and internal factors.
part a: list two external factors that influence the cell cycle and briefly describe them. (2 points)
part b: list two internal factors that influence the cell cycle and briefly describe them. (2 points)

External factors include physical and chemical signals. Growth factors are proteins that stimulate cell division. – Most mammal cells form a single layer in a culture dish and stop dividing once they touch other cells. Two of the most important internal factors are kinases and cyclins.

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands