“M期” refers to the “M phase” in the cell cycle, which is a crucial stage where cell division occurs. During this phase, a single cell divides into two daughter cells, ensuring that each new cell receives an identical set of chromosomes. This process is essential for growth, development, and tissue repair in organisms. The M phase consists of several key processes, including mitosis and cytokinesis. Mitosis is the division of the cell's nucleus, while cytokinesis is the division of the cytoplasm. Together, these processes ensure that genetic material is accurately distributed, maintaining the integrity of the organism's genetic information.