Chromosomes condense in prophase of mitosis

Steps:

• Identify the process: Mitosis involves chromosome condensation for visibility and separation.
• Recall phases: Interphase has decondensed chromatin; prophase begins condensation.
• Match to question: Condensation and visibility occur at prophase start.
• Eliminate others: Cytokinesis is cytoplasmic division after mitosis.

Why D is correct:

• Not enough information: Diagram missing, but assuming D labels prophase, it matches definition of chromosome condensation.

Why the others are wrong:

• A: Likely interphase; chromosomes are not yet condensed or visible.
• B: Possibly metaphase; chromosomes are already condensed and aligned.
• C: Perhaps anaphase; chromosomes separate without new condensation.

Final answer: D