AP BIOLOGY

Detailed explanation-1: -Animal cell cleavage furrow formation is caused by a ring of actin microfilaments called the contractile ring, which forms during early anaphase.

Detailed explanation-2: -During cytokinesis in animal cells, a ring of actin filaments forms at the metaphase plate. The ring contracts, forming a cleavage furrow, which divides the cell in two.

Detailed explanation-3: -Cell division ends as the cytoplasm divides into two by the process of cytokinesis. Except for plants, cytokinesis in eucaryotic cells is mediated by a contractile ring, which is composed of actin and myosin filaments and a variety of other proteins.

Detailed explanation-4: -Roles of microtubules in cytokinesis Microtubules of the bipolar spindle dictate the position of the cleavage plane midway between the two asters. Subsequently, microtubules of the spindle midzone promote ingression of the cleavage furrow and the completion of cytokinesis.