Answer:
Revolving nosepiece
Step-by-step explanation:
The revolving nosepiece (also called the turret) is the part of the microscope we can turn in order to view an object through different objective lenses. Objective lenses, which provide different levels of magnification (usually 4x, 10x, 40x, and 100x), are all attached to the revolving nosepiece. It allows us to switch lenses from those that provide less magnification to those that provide more. This is how we can see more details on an object we're observing.
You can see what this part of the microscope looks like in the image attached below: