What structure forms to signify the completion of Cytokinesis?

The formation of a cleavage furrow signifies the completion of cytokinesis in animal cells. During cytokinesis, the cytoplasm of a parental cell is divided into two daughter cells. The cleavage furrow is an indentation that forms in the cell membrane, typically at the equatorial region of the cell. This furrow progressively deepens as the contractile ring composed of actin and myosin filaments tightens, ultimately pinching the cell in two.

This process is crucial for ensuring that each daughter cell receives an equal share of the cytoplasm and organelles. In contrast, the metaphase plate, chromosome pairs, and spindle fibers are structures associated with earlier stages of cell division, such as mitosis, rather than with cytokinesis itself. Thus, the cleavage furrow is specifically indicative of the final stage of cell division when the physical separation of the cells takes place.