What is the primary structure used for supporting the microscope during handling?

The arm of a microscope is designed to provide structural support and a safe way to handle the instrument. It connects the base to the body of the microscope, allowing users to lift and move the microscope securely without risking damage to sensitive components. The arm is typically sturdy and ergonomic, facilitating easy transportation while maintaining the stability required for precise observation.

In contrast, the stage is the platform where slides are placed for viewing but does not aid in the handling of the microscope itself. The condenser focuses light onto the specimen but is not involved in supporting the microscope. The iris diaphragm controls the amount of light that reaches the specimen, but it too does not serve a role in the structural support during handling. Thus, the arm is the primary structure used to support the microscope during handling, ensuring safe and effective use of the instrument.