Anaphase: Spindle Microtubules Shorten

Steps:

• Identify mitosis stages: prophase (chromatin condenses), metaphase (chromosomes align), anaphase (chromosomes separate), telophase (nuclear reformation).
• Evaluate statement 1: centriole replication occurs during S phase of interphase, before mitosis begins.
• Evaluate statement 2: spindle microtubules shorten in anaphase to pull sister chromatids apart.
• Evaluate statement 3: chromatin condenses in prophase to form visible chromosomes.
• Conclude the photomicrograph depicts anaphase, where only statement 2 applies.

Why C is correct:

• Anaphase definition: kinetochore microtubules depolymerize and shorten, separating chromatids toward poles.

Why the others are wrong:

• A: Includes incorrect centriole replication (interphase) and chromatin condensation (prophase).
• B: Includes incorrect centriole replication (interphase event).
• D: Describes prophase condensation, not the separation stage shown.

Final answer: C