What organelle causes mitosis?

Mitosis is primarily regulated by the centrosome, which organizes the microtubules that form the spindle apparatus, essential for separating chromosomes during cell division. While the centrosome itself is not an organelle that directly causes mitosis, it plays a critical role in facilitating the process. Additionally, other organelles like the nucleus and the endoplasmic reticulum contribute to the overall process by ensuring proper chromosome replication and distribution.