Question

question
how do the coarse and fine focus knobs work on a brightfield microscope?
the focus knobs move the eyepieces farther apart or closer together.
the focus knobs move the stage toward and away from you as you are looking at the microscope.
the focus knobs move the stage up and down.

Explanation:

The coarse and fine focus knobs on a bright - field microscope adjust the distance between the specimen on the stage and the objective lens by moving the stage up and down. This is to bring the specimen into sharp focus. Moving the eyepieces apart or together adjusts inter - pupillary distance, and moving the stage toward or away from the observer is not related to focusing.

Answer:

The focus knobs move the stage up and down.