The combining form organ(o) means which body part?

• A. Mouth
• B. Bone
• C. Testis
• D. Organ

Answer: (D)

The main idea here is that organ(o) denotes a general body part that is an organ—a functional part of the body made up of tissues, such as the heart, liver, or kidneys. In medical terminology, organ- is used to speak about organs in a broad sense, not a specific structure. Mouth, bone, and testis have their own distinct roots (stomat/o for mouth, oste/o for bone, orch/o or testicul/o for testis), so organ(o) is the form that points to the general category of organs. That’s why the best choice is organ.