Answer:
The chromosomes become visible under a light microscope during prophase stage of mitosis
Explanation:
Propohase -
The first phase of mitosis , in which the chromosomes becomes visible , as a distinct structure , the nuclear envelope breaks down and the spindle formation takes place .
Hence , this stage is visible under the light microscope.
The next phase is the metaphase , in which the chromosomes line up in middle of cell .
In the third phase , i.e. , the anaphase , the chromosomes moves towards the opposite sides of the vcell .
In the fourth phase , i.e. , the telophase , the two nuclei are formed .
In the last stage , i.e. , cytokinesis , the cell finally divides into two daughter cells .