Final answer:
The flattened, hollow structure formed during the final stages of plant cell division is called the cell plate, which leads to the separation of the two daughter cells during cytokinesis.
Step-by-step explanation:
The final stages of cell division in plant cells involve the formation of a flattened, hollow structure called the cell plate. This structure is located at the cell's equator. During cytokinesis, which is the final stage of eukaryotic cell division, the cytoplasm splits into two, and the cell divides. In plant cells, a cell plate forms along the equator of the parent cell. Subsequently, Golgi vesicles coalesce to form a phragmoplast, from which the cell plate arises, ultimately leading to the formation of a plasma membrane and cell wall on each side of the cell plate, separating the two daughter cells.