Which of the following is NOT a phase in the cell cycle?

The cell cycle consists of several key phases that describe the process through which a cell grows and divides. The G1 phase is a growth phase where the cell prepares for DNA replication, the S phase is where DNA synthesis occurs and the genetic material is duplicated, and the M phase is the mitotic phase where the cell divides into two daughter cells.

The option that is not a recognized phase in the cell cycle is referred to as "M2 phase." This terminology is not standard and does not represent a phase in the cell cycle. Instead, the M phase encompasses the processes of mitosis and cytokinesis without any subclassification into sub-phases labeled as M1 or M2. Therefore, identifying M2 phase as not a part of the established cell cycle phases aligns with the understanding of cellular growth and division accurately.