Answer: Centromere.
- A Telomere
- B Centromere
- C Kinetochore fibre
- D Chiasma
Correct answer: B. Centromere
Explanation: Sister chromatids are joined at the centromere, the constricted region where the kinetochores assemble.
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.