Which organelle helps align chromosomes during cell division in animal cells?

• A. Centriole
• B. Nucleolus
• C. Ribosome
• D. Mitochondrion

Answer: (A)

During animal cell division, the spindle apparatus organizes the movement and alignment of chromosomes. The centrosome, which contains a pair of centrioles, helps build and anchor the microtubules that form the spindle poles. These microtubules attach to kinetochores on the chromosomes and generate the forces that pull sister chromatids toward opposite poles, lining them up at the center of the cell (the metaphase plate). Without this spindle organization provided by the centrioles, chromosomes wouldn’t align properly for equal segregation. The nucleolus is where rRNA is produced, ribosomes make proteins, and mitochondria generate energy, so they don’t directly govern chromosome alignment.