A decisive characteristic of life is the reproductive capacity of cells, which it does through a collection of highly complex and ordered regulatory process commonly known as the cell cycle. The cell cycle combines DNA replication with chromosomal segregation in an oscillatory manner. In this way, the cell cycle coordinates the precise replication of the genome through specific events to ensure that the duplicated genetic material is distributed equally to each daughter cell. The repetition of this process leads to the exponential proliferation of cells. This process is classically described as interphase and mitosis (M) phase. Most of the cell cycle is in interphase, which encompasses Gap 1 (G1), synthesis (S), and Gap 2 (G2) phases. During the interphase, the cell grows, replicates genetic materials, and repairs DNA damage and replication errors. M phase, a relatively short period, consists of prophase, metaphase, anaphase, and telophase, which completes the equal distribution of genome and cytoplasmic components. Following interphase, most nondividing cells exit the cell cycle at G1 into G0 phase (quiescence). G0 was originally used to describe cells that are not in the cell cycle but with the potential for division. The rate of cell cycling varies with the developmental stage and cell type. In general, the cell cycle is most active during development, as cells in early embryos can proliferate and differentiate to form tissues and organs. The cell cycle involves numerous life processes, and it is closely related to the growth and proliferation of eukaryotic cells, development of organisms, regulation of DNA damage repair, and occurrence of diseases.