What is the role of S cyclin-dependent kinases (Scdks) in the cell cycle?

• A. They initiate the process of mitosis.
• B. They inhibit DNA replication to prevent premature cell division.
• C. They are responsible for cell growth during the G1 phase.
• D. They trigger the transition from G1 phase to S phase by activating DNA replication processes.

Answer: (D)