Answer :
There are way more than four, so this photo should help you
I know the eyepiece is definitely one.
The stage perhaps would be one.
Maybe the coarse adjustment knob and the fine adjustment knob.
and maybe the objectives
I know the eyepiece is definitely one.
The stage perhaps would be one.
Maybe the coarse adjustment knob and the fine adjustment knob.
and maybe the objectives
![View image maryanneh2018](https://us-static.z-dn.net/files/d38/9a83e4d86f2a1804dc4bc6a0977cfde9.gif)