Which of the following molecules is synthesized at specific times during the cell cycle and forms an active complex with a kinase?

A)PDGF
B)MPF
C)Cdk
D)cyclin

D. Cyclin

Explanation:

Cyclins drive the events of the cell cycle by partnering with a family of enzymes called the cyclin-dependent kinases (Cdks). A lone Cdk is inactive, but the binding of a cyclin activates it, making it a functional enzyme and allowing it to modify target proteins.

eukarya because is is like alche and b is bacteria and d is animals

explanation:

the scientific method.