During telophase II, which event occurs?

During telophase II, which event occurs?

• A. The spindle fibers disappear, and a nuclear membrane forms around each set of chromosomes.
• B. Centromeres divide and chromatids move toward the poles.
• C. Crossing over occurs between homologous chromosomes.
• D. Chromosomes condense prior to separation.

Answer: (A)

In telophase II, the cell finishes separating the chromatids and begins to reassemble its nuclei. The spindle fibers break down, and a nuclear envelope forms around each set of chromosomes that has arrived at the poles. This creates distinct nuclei for the eventual haploid cells, and cytokinesis often completes to produce four separate haploid cells. That combination—disassembly of the spindle and re-formation of a nuclear membrane around each chromosome set—is what defines telophase II. The other events happen at other stages: centromeres splitting and chromatids moving to the poles occurs in anaphase II; crossing over happens in prophase I; and chromosomes condense before they separate, during prophase (or early meiosis), not in telophase II.

In telophase II, the cell finishes separating the chromatids and begins to reassemble its nuclei. The spindle fibers break down, and a nuclear envelope forms around each set of chromosomes that has arrived at the poles. This creates distinct nuclei for the eventual haploid cells, and cytokinesis often completes to produce four separate haploid cells.

That combination—disassembly of the spindle and re-formation of a nuclear membrane around each chromosome set—is what defines telophase II. The other events happen at other stages: centromeres splitting and chromatids moving to the poles occurs in anaphase II; crossing over happens in prophase I; and chromosomes condense before they separate, during prophase (or early meiosis), not in telophase II.