Cytokinesis in animal cells is characterized by which process?

• A. No centrosomes present; a cell plate forms
• B. Cleavage furrow forms and the cell membrane pinches in
• C. The nucleus disappears during cytokinesis
• D. Cleavage, 2 daughter cells separate

Answer: (D)

In animal cells, cytokinesis is driven by a contractile ring of actin that forms a cleavage furrow. This ring pulls the cell membrane inward, pinching the membrane and cytoplasm to split the cell into two separate daughter cells. This mechanism—membrane constriction to divide the cytoplasm—is the hallmark of animal cell cytokinesis. The alternative of forming a cell plate is how plant cells complete cytokinesis, not animal cells, because plants build a new cell wall in the center rather than pinching the membrane. The idea that the nucleus disappears isn’t accurate for cytokinesis; the nucleus has already divided during mitosis, and cytokinesis finishes cytoplasmic division while nuclei are re-established in the two new cells.