Biology

The correct answer is: D.Two sister chromatids

During the S phase (Synthesis phase), each chromosome is replicated to form two identical sister chromatids, which are connected at a region called the centromere. These sister chromatids remain attached to each other until they are separated during mitosis (M phase).

Here’s a breakdown of the other options:

A.Two separate chromatids: This is not accurate during the S phase. The chromatids are not yet separate; they remain attached as sister chromati...