Based on the data, which of the following best describes the relationship between cyclin-dependent kinases and the cell cycle?

Core Concept

Cyclin-dependent kinases play a crucial role in driving the cell cycle forward by phosphorylating and activating downstream targets. They are essential for cell cycle progression and are active during different stages of the cell cycle. Options A and C are incorrect because cyclin-dependent kinases are active during multiple phases of the cell cycle, not just G1. Option D is incorrect because cyclin-dependent kinases are essential for cell cycle progression.