During which stage of mitosis are chromosomes most visible?

The visibility of chromosomes is primarily enhanced during the stage of mitosis called metaphase. At this stage, chromosomes align at the equatorial plane of the cell, and they are fully condensed and shorter, which makes them distinctly visible under a microscope. The chromatin that condensed during prophase becomes even more organized, allowing for a clear observation of individual chromosomes.

While prophase is also a critical stage for chromosome visibility, they are still undergoing condensation and not yet at their maximum visibility, as they are not fully aligned. Thus, while they are indeed visible in prophase, they reach optimal visibility at metaphase. Other stages like interphase involve the DNA in a more relaxed, less organized state, making chromosomes difficult to distinguish, and telophase marks the beginning of chromosome decondensation, further reducing their visibility. Therefore, while prophase allows for some visibility of chromosomes, it is metaphase that showcases them at their most distinct and visible form.