The spindle lines up the chromosomes down the center of the cell

during metaphase in mitosis. This process ensures that each daughter cell receives an equal and complete set of chromosomes. The spindle apparatus, which is composed of microtubules, attaches to the centromere region of each chromosome and pulls them towards the cell equator. This alignment of the chromosomes at the center of the cell is important for proper segregation during anaphase, where the sister chromatids separate and move towards opposite poles of the cell.