In which phase does a cell separate in the cell cycle?

During the cell cycle, the phase in which a cell separates into two daughter cells is specifically during mitosis. This phase is characterized by the systematic process of cell division, where the chromosomes are accurately segregated and distributed into the two new cells. Mitosis includes distinct stages: prophase, metaphase, anaphase, and telophase, culminating in cytokinesis, the final separation of the cellular membrane that fully divides the cell.

Interphase, which includes the G1, S, and G2 phases, is a period of growth and preparation for cell division, but does not involve the actual separation of the cell. During the S phase, DNA is replicated, while the G2 phase focuses on further preparation for mitosis. Therefore, while these phases are critical to the cell cycle, the physical separation of the cell occurs exclusively in mitosis, making it the correct answer.