What happens during Anaphase II of meiosis?

During Anaphase II of meiosis, the key event is the separation of sister chromatids, which are identical copies of a chromosome. This separation occurs when the spindle fibers attached to the centromeres begin to shorten, pulling the sister chromatids apart towards opposite poles of the cell. This movement ensures that each new daughter cell will receive an equal and complete set of chromosomes when the cells eventually divide.

The process is crucial for maintaining the correct number of chromosomes in the resulting gametes. As the chromatids are separated, each pole of the cell ends up with one copy of each chromosome, setting the stage for the eventual formation of four haploid cells.

In contrast, the other options describe events that do not occur during Anaphase II. Homologous pairs align during Metaphase I rather than Anaphase II, the breakdown of the nuclear envelope happens at the beginning of meiosis (prophase), and cytokinesis, which involves the division of the cytoplasm and cell membrane, typically follows the completion of meiosis rather than being a characteristic event of Anaphase II itself.