Which combining form means movement or motion (often used with muscles)?

• A. Kinesi/o
• B. Muc/o
• C. Medi/o
• D. Psych/o

Answer: (A)

Movement or motion is conveyed by the combining form kinesi/o, which comes from the Greek kinein meaning "to move." This stem appears in terms like kinesiology, the study of body movement, and in other muscle- or movement-related words such as kinetic, dyskinesia, and kinesia. The other options refer to unrelated concepts: muc/o means mucus, mucous membranes; medi/o means middle or the middle region; psych/o relates to the mind or mental processes. So for a term describing movement, especially involving muscles, kinesi/o is the correct forming.