What part of a microscope is used to sharpen the image?

The focus adjustor is a crucial component of a microscope that allows the user to sharpen the image being viewed. When observing a specimen, the focus adjustor helps to bring the image into clearer resolution by making fine adjustments to the distance between the objective lens and the specimen. This is essential for obtaining a well-defined view of the details within the sample, ensuring that the observer can accurately analyze and study the specimen.

In contrast, the other parts have different functions. The stage is where the specimen slides are placed during observation, while the viewfinder is used for aligning the eyepiece with the eye but does not sharpen the image itself. The magnification knob increases the size of the image but does not necessarily improve clarity without proper focusing. Therefore, the focus adjustor is the key component responsible for enhancing the image clarity in a microscope.