What action occurs during telophase of mitosis?

During telophase of mitosis, one of the key events is the reformation of the nuclear envelope around the separated sets of chromosomes. As the cell completes the process of mitosis and moves towards cytokinesis, the chromosomes that had previously condensed and aligned during metaphase now begin to de-condense back into a more relaxed form. The nuclear envelope forms anew around each set of chromosomes, creating two distinct nuclei within the cell. This is crucial for ensuring that each daughter cell receives a complete set of genetic material encapsulated within its own nucleus once the cell ultimately divides.

In contrast, during prophase, the chromosomes condense and become visible, while the nuclear envelope fragments. DNA replication occurs earlier during the S phase of interphase, not in mitosis itself. Thus, the action characteristic of telophase is specifically the re-formation of the nuclear envelope, which marks a significant transition in preparing for the end of cell division.