Question

when an image is not in focus under high power when you clearly saw the image under low power, what should you never do first?
clean the high - power objective with lens paper
go back to low power to make sure the image is centered and clear
refocus using the fine adjustment and readjust lighting.
call the instructor for assistance.

Explanation:

When switching to high power from a focused low-power image, standard microscope protocol first involves checking centering, using fine focus, or adjusting lighting. Cleaning the lens is not the first step because the image was clear on low power, so lens dirt is not the immediate suspected issue. Calling for assistance is also premature before basic troubleshooting. The first action you should NEVER take is cleaning the high-power objective, as it's an unnecessary step at this stage.

Answer:

A. Clean the high-power objective with lens paper