Answer:The cell was no longer visible because the image wasn't centered before switching to higher objective of 40X.
Explanation:
While using microscopes, the image will approximately remain in focus if you adjust the focus during change of magnification. Therefore, there is need to always adjust the focus during change in magnification.
If object is not centered before switching to a higher power objective, object will not be visible.
To avoid this, center the object before switching to a higher power objective. This will help you find the object after switching the objective. And it is also important to use fine focus and not coarse focus.
The answer is b) Surveying opinions of fellow classmates
Aggy is a very long day and I don't have to go back and forth to the store to pick up a little bit and I have been there for me to do it again and .