Which event occurs during metaphase?

• A. Chromosomes become visible, nuclear envelope dissolves, spindle forms
• B. The chromosomes become longer, thinner, and less distinct
• C. Chromosomes line up in the middle of the cell
• D. The cytoplasm divides

Answer: (C)

Metaphase is the stage when the spindle is ready and the condensed chromosomes line up along the middle of the cell, forming the metaphase plate. Each chromosome is held by microtubules attached to kinetochores from opposite spindle poles, aligning so that the sister chromatids will be pulled apart accurately in the next stage. This orderly arrangement ensures equal distribution of genetic material to the two daughter cells. The other described events occur at different times: earlier, chromosomes condense and the nuclear envelope breaks down as the spindle forms; later, the cytoplasm divides during cytokinesis.