Final answer:
The angular diameter of an object can be expressed in degrees (°), radians (rad), and arcminutes (').
Step-by-step explanation:
The angular diameter of an object can be expressed in all of the above units: degrees (°), radians (rad), and arcminutes (').
The angular diameter is a measure of the size of an object as it appears to an observer. It is the angle subtended by the object at the observer's location. The unit used to express this angle can vary depending on the context. In astronomy, for example, the angular diameter of celestial objects is often measured in arcminutes. In physics, degrees and radians are commonly used.