Cancer growth and cell division
Cyclin dependent kinase is the answer for the first question. Cyclin concentration increases during m phase and falls in g1 s and g2 phase as it is degraded. Cdk is always present in the cell but gets activated during m phase, when cyclin is present. (cyclin dependent)

Cancer cells do not require growth factors to stimulate cell division. They have mutations which disrupts the normal cell cycle regulation. Now can you think what should be the answer ?