There are around 12 parts in a microscope. Here are a couple:
Eye piece- Used to look through the microscope
Arm- Used to hold the microscope
Lower Power Objective Lense- The lense with x10 magnification
High Power Objective Lense- The Lense with x20 and x40 magnification
Base- The bottom of the microscope
Light Source- Where the light comes from
Missing PArts: Fine and COurse Adjustment Knob, Nose Piece, Stage CLips, Diaphragm, Stage.