You are looking at very lightly stained cells under the microscope, and you want to increase the contrast so that you can see them "better." You _ the iris diaphragm to _ the light.
A) open, dim
B) close, increase
C) open, increase
D) close, dim

Question

Quizplus · Accepted Answer

Closing the iris diaphragm reduces the amount of light entering the microscope, which increases the contrast of the image, making lightly stained cells easier to see.

You Are Looking at Very Lightly Stained Cells Under the Microscope