What process occurs during cytokinesis?

Cytokinesis is the final stage of cell division, which follows the process of mitosis or meiosis. During cytokinesis, the cytoplasm of a parental cell is divided into two daughter cells, each containing a complete set of organelles and genetic material. The correct answer highlights that the process involves the cell membrane pinching inwards, ultimately leading to the formation of two distinct, identical daughter cells.

This pinching action is facilitated by a structure known as the contractile ring, composed of actin and myosin filaments, which constricts the middle of the cell. As the contractile ring tightens, it creates a cleavage furrow that deepens until the membrane is finally pinched in two.

In contrast, the other options refer to events that occur during earlier stages of cell division. Chromosomes coil and align during prophase and metaphase, the nuclear membrane disassembles during prophase, and sister chromatids separate during anaphase. These processes are crucial for ensuring that genetic material is accurately distributed but do not pertain to the specific mechanism of cytokinesis.