Answer:
A checkpoint is one of several points in the eukaryotic cell cycle at which the progression of a cell to the next stage in the cycle can be halted until conditions are favorable.
Explanation: Or
Oscillations in the activities of various cyclin-Cdk complexes leads to the initiation of various cell-cycle events. Thus, activation of S-phase cyclin-Cdk complexes initiates S phase, while activation of M-phase cyclin-Cdk complexes triggers mitosis.
