Answer:
metaphase
Step-by-step explanation:
The cell cycle control system initiates chromosome segregation only after metaphase has occurred.
At metaphase, the chromosomes of a dividing cell align at the equator to form what is known as the metaphase plate. Each chromosome gets engaged by spindles from the opposite sides of the poles at the kinetochore of the centromere.
Thereafter, the cell proceeds to the anaphase stage during which the shortening of the spindle fibers pulls the chromosome apart into sister chromatids and this eventually causes the sister chromatids to start migrating to opposite poles of the cell.