Here's a breakdown of why:

* Prophase: Chromosomes condense and become visible.

* Metaphase: Chromosomes line up at the center of the cell (metaphase plate).

* Anaphase: The centromeres of each chromosome split, and the sister chromatids are pulled apart by spindle fibers towards opposite poles of the cell.

* Telophase: The chromosomes reach the poles and begin to uncoil. The nuclear envelope reforms around each set of chromosomes, and the cell divides (cytokinesis).