Here's why:

* Plant cells have rigid cell walls: Animal cells do not have cell walls. This means plant cells need a special structure to divide their rigid cell walls.

* Cell plate formation: The cell plate forms during cytokinesis in plant cells. It is a new cell wall that grows between the two daughter cells. Vesicles from the Golgi apparatus fuse together at the middle of the parent cell, bringing cell wall material and other components to form the cell plate.

In contrast, animal cells:

* Cleavage furrow: Animal cells divide using a cleavage furrow. This is a constriction in the cell membrane that pinches inwards, eventually separating the two daughter cells.

So, the cell plate is the key structural difference between plant and animal cell cytokinesis.