What is cytokinesis?

Cytokinesis is really just a fancy word for cell division. It is an important stage in both mitosis and meiosis that allows 2 new cells to be produced from 1. The way this is achieved is through the use of a contractile ring.A contractile ring is just a ring of proteins within the cell that form a ring around the edge of the cell, under the cell membrane. They are able 'contract'/'pinch'/'shrink'/or 'make smaller'. Imagine a ring that's placed around a marshmallow that's able to squeeze and squeeze until one marshmallow becomes two.As the contractile ring squeezes, it pinches the cell membrane so much to the point that a cleavage furrow forms.A cleavage furrow is really just a inward folding or a little ridge of the cell membrane formed due to the squeezing.Eventually, the ring squeezes so much that the cell is able to divide along the cleavage furrow so that 2 cells are formed from the original.Each cell is surrounded by its own plasma membrane and has the ability to undergo cytokinesis all over again!