What is the process of cytokinesis responsible for?

Cytokinesis is the process that specifically refers to the division of the cytoplasm during cell division. This occurs after the mitotic phase, where the nucleus of the cell has already divided (a process known as mitosis). During cytokinesis, the cell's cytoplasm and its organelles are evenly distributed between the two daughter cells, ensuring that each new cell has the necessary components to function properly.

The importance of cytokinesis lies in its role in completing the cell division cycle. The correct functioning of this process allows for the creation of two distinct and viable daughter cells from one parent cell. In many eukaryotic cells, this process involves the formation of a contractile ring that pinches the cell membrane, ultimately leading to the separation of the cells.

The other options refer to different cellular processes: the division of the nucleus is completed during mitosis, replication of DNA occurs during the S phase of interphase, and the formation of spindle fibers is crucial for the separation of chromosomes during mitosis, but none of these processes encompass the specific action of cytokinesis.