Answer: Prophase I.
- A Prophase II
- B Metaphase I
- C Prophase I
- D Anaphase II
Correct answer: C. Prophase I
Explanation: Crossing over (exchange of DNA between homologous chromosomes) occurs during Prophase I of meiosis. It generates genetic variation.
The cell cycle: G1 (growth and preparation), S (DNA replication, chromosome number stays 2n but DNA content doubles), G2 (final checks before division), and M (mitosis itself) - together, G1+S+G2 make up interphase.
Concept context
Mitosis and meiosis: how cells divide for growth, repair, and reproduction.