Why might a scientist use colored dyes when viewing items under a compound light microscope?

Biological samples or specimens need to be stained with dyes when viewing them under a compound microscope so that they become more visible. The biological specimens usually lack colour or lack contrast in colour due to which they cannot be visualized properly if they are not marked by colouring dyes. A specific dye will strain a specific part of the specimen and hence, it will be easier to identify that part.