Final answer:
The contractile ring involved in animal cell division is made up of actin filaments. Actin works alongside myosin in the process of cytokinesis to form the cleavage furrow, resulting in the separation of the cell into two daughter cells.
Step-by-step explanation:
The contractile ring that pinches the cytoplasm in two during the division of an animal cell is composed of actin filaments.
Actin and myosin work together during cell division to form the cleavage furrow, which is crucial in the process of cytokinesis that ultimately divides the cell into two separate daughter cells.
Actin, a protein that can polymerize into long fibrous structures, forms the contractile ring by interacting with myosin, which uses ATP to generate a force that aids in cell division.