Final answer:
Actin filaments form a contractile ring that creates the cleavage furrow, allowing an animal cell to split into two during cytokinesis.
Step-by-step explanation:
The structures that help create the cleavage furrow in an animal cell are primarily actin filaments that form a contractile ring. This ring of actin microfilaments contracts and pulls the plasma membrane inward at the cell's equator, eventually leading to the cell being divided into two. Unlike in plant cells where a cell plate must form due to the presence of rigid cell walls, animal cells use this flexible method for cytokinesis.
In the process of cytokinesis, which follows anaphase, the cleavage furrow appears as a fissure that deepens as the actin ring contracts. This contractile band is crucial for cytoplasmic division, ensuring that each new cell, be it the stem cell or the functional cell, receives the necessary components to continue functioning or to enter its own cell cycle for future divisions.
The cleavage furrow is formed during animal cell cytokinesis as a result of the contractile ring composed of actin filaments. This contractile ring forms just inside the plasma membrane at the former metaphase plate. As the actin filaments pull the equator of the cell inward, a fissure called the cleavage furrow is created. The furrow deepens as the actin ring contracts, eventually leading to the division of the cell into two separate daughter cells.