Final answer:
Spindle fibers break down during telophase, the final phase of cell division, preparing the cell for the next division cycle.
Step-by-step explanation:
Spindle fibers actually break down during the telophase stage of cell division. Cell division comprises multiple stages: prophase, metaphase, anaphase, and telophase, forming the acronym PMAT. During the prophase, the spindle fibers form. In metaphase, the chromosomes align in the middle of the cell. The Anaphase is where the cells start to pull apart. Finally, during telophase, the spindle fibers break down, and the chromosomes are completely separated, leading to cytokinesis where the rest of the cell then divides. This is critical as it's the final phase of cell division and it prepares the cell for the next cycle of division.
Learn more about Cytokinesis