Cytokinesis halves DNA mass by cell division

Steps:

• DNA doubles during S phase of interphase via replication.
• Mitosis (prophase to telophase) separates duplicated chromosomes without reducing total DNA mass in the single cell.
• Anaphase pulls sister chromatids to poles, maintaining doubled mass in one cell.
• Cytokinesis divides the cell into two daughters, each with half the original DNA mass.

Why B is correct:

• Cytokinesis completes cell division, splitting the cytoplasm and nuclei to form two cells, halving DNA mass per cell per the cell cycle definition.

Why the others are wrong:

• A. Anaphase separates chromatids but keeps all DNA in one undivided cell.
• C. Interphase features DNA replication in S phase, doubling mass.
• D. Prophase condenses chromosomes without altering DNA mass.

Final answer: B