The drug cytochalasin b blocks the function of actin. which of the following aspects of the animal cell cycle would be most disrupted by cytochalasin b?
a. spindle formation
b. spindle attachment to kinetochores
c. cell elongation during anaphase
d. cleavage furrow formation and cytokinesis

d. cleavage furrow formation and cytokinesis

Explanation:

Cytochalasin B is a cell permeable toxin produced by fungi. It inhibits actin polymerization and interaction of actin filaments. Cytokinesis is the process in which the cell undergoes cytoplasmic division to form two new cells. It begins in late anaphase and is completed by the end of telophase. It begins by the production of cleavage furrow on the cell surface. This furrow is formed by the contractile ring which in turn is composed of actin and myosin filaments along with other regulatory proteins.

When actin polymerization is inhibited by cytochalasin B, the contractile ring is not able to form so the cleavage furrow does not appear which ultimately inhibits cytokinesis.