I'm not really sure, but I guess skin colour isn't passed genetically?
The answer is c because it make the most since if you put in the word in the definition
Answer:
when G1/S cyclin-CDK is activated. Expression of G1/S cyclins is regulated by E2F proteins
Explanation:
I've found this on Google
Commitment to cell division occurs at Start when G1/S cyclin-CDK is activated. Expression of G1/S cyclins is regulated by E2F proteins in conjunction with pRB proteins.. Mitogens stimulated cell division by increasing the amount of G1 cyclins.