Which structure holds two sister chromatids together?

• A. Chromatids
• B. Chromosome
• C. Centromere
• D. Nucleus

Answer: (C)

The essence here is the place where the two identical copies of DNA stay connected after replication. That connection happens at a region called the centromere, which holds the sister chromatids together and coordinates their movement during cell division through cohesion proteins and the kinetochore attachment. This specific role is what makes the centromere the correct answer.

Understanding the others helps too: chromatids are the duplicated halves themselves, not the connector; a chromosome refers to the whole unit that contains both chromatids and the centromere, not the glue that holds them together; and the nucleus is simply the organelle that houses the genetic material, not the structure that binds the two chromatids.