Retinoblastoma gene regulates-
Ans. is 'a' i.e., G1- S phaseo Phosphorylation of RB is a molecular "On-off' switch for cell cycle.o It regulates cell cycle at G,- S phase (has been explained in details in previous explanations).
Gi - S phase
G2 - M phase
Go - S1 phase
S - G1 phase