Simple, we are learning about new things every day we as a human race learn something new about our world
Mitosis takes place in four stages: prophase (sometimes divided into early prophase and prometaphase), metaphase, anaphase, and telophase. You can learn more about these stages in the video on mitosis. In cytokinesis, the cytoplasm of the cell is split in two, making two new cells.
(Hope this helps)
Animal cells form animals
Plant cells form plants