Chromosomes can be seen clearly during mitosis and meiosis, specifically during the metaphase stage.

Here's why:

* Chromosomes condense: During these cell divisions, the chromosomes condense, becoming much thicker and shorter. This makes them easier to see under a microscope.

* Alignment at the metaphase plate: In metaphase, the condensed chromosomes line up along the center of the cell (the metaphase plate). This arrangement allows for clear visualization of their structure and individual chromosomes.

While chromosomes are present in the nucleus of a cell throughout its life cycle, they are only visible as distinct structures during cell division when they are highly condensed.