What occurs during anaphase of mitosis?

During anaphase of mitosis, sister chromatids separate and move toward opposite poles of the cell. This separation is crucial for ensuring that each daughter cell receives an identical set of chromosomes following cell division. The process begins when the centromere that holds the sister chromatids together splits, allowing the spindle fibers to pull each chromatid to opposite ends of the cell. This action is vital for maintaining the correct number of chromosomes in the resulting daughter cells, which is essential for proper cell function and genetic stability.

The other processes mentioned in the options occur at different stages of mitosis. For instance, chromosome alignment at the center happens during metaphase, while the disintegration of the nucleus is observed during prophase, and condensation of chromosomes occurs early in the prophase stage as the chromatin becomes more compact.