Stage 2 of the cell cycle is S phase, which stands for synthesis.

Here's what happens in S phase:

* DNA Replication: The cell's DNA is copied, ensuring that each daughter cell receives a complete set of genetic material.

* Centriole Duplication: In animal cells, the centrioles, which play a role in cell division, are also duplicated.

S phase is crucial because it ensures that each new cell has the correct amount of genetic material. It's a tightly regulated process, with checkpoints ensuring that DNA replication is completed accurately before moving on to the next stage.