Answer: The four stages of mitosis are prophase, metaphase, anaphase and telophase.
Prophase: chromatin condenses into thick, visible chromosomes, each made of two sister chromatids. The centrioles move to opposite poles and spindle fibres begin to form. The nuclear membrane and nucleolus disappear.
Metaphase: chromosomes become fully condensed and arrange themselves in one plane at the equator of the cell (metaphase plate). Spindle fibres attach to the centromere of each chromosome.
(Anaphase: the centromeres split and sister chromatids are pulled to opposite poles. Telophase: chromatids reach the poles, uncoil, and new nuclear membranes form, giving two daughter nuclei.)