Question

how does cytokinesis occur in a dividing animal cell?
by the formation of a cleavage furrow
by the formation of a strip of new membrane that separates the daughter cells
by the mitotic spindle pulling the daughter cells apart
by the formation of a cell plate

Explanation:

In animal cell cytokinesis, a cleavage furrow forms. It is a contractile ring (made of actin and myosin filaments) that pinches the cell membrane inward. A cell plate forms in plant cells (not animal cells). The mitotic spindle is mainly involved in chromosome separation during mitosis, not the final separation of daughter cells in cytokinesis. A strip of new membrane forming to separate daughter cells is not the typical mechanism in animal cell cytokinesis.

Answer:

By the formation of a cleavage furrow