During which phase of mitosis does the nuclear envelope reappear?

The phase of mitosis during which the nuclear envelope reappears is telophase. This occurs after the chromosomes have been separated and moved to opposite poles of the cell. During telophase, the chromosomes begin to de-condense back into chromatin, allowing the nuclear envelope to reform around each set of chromosomes. This marks the end of mitosis and sets the stage for the cell to enter the next phase, cytokinesis, which is when the cytoplasm divides.

In contrast, during prophase, the nuclear envelope breaks down and the chromosomes condense, making the genetic material visible under a microscope. Metaphase is characterized by chromosomes aligning at the cell's equatorial plane, and interphase is not a phase of mitosis at all; it refers to the period of the cell cycle when the cell is preparing for mitosis, including DNA replication. Thus, telophase is the definitive phase for the reformation of the nuclear envelope, highlighting its essential role in restoring nuclear structure as the cell prepares to complete division.