Which combining form means extremity, top, or extreme point?

• A. Apex/o
• B. Acro/o
• C. Arc/o
• D. Termin/o

Answer: (C)

Extremity and top are captured by the combining form acro/o. It designates either the farthest extremities (hands and feet) or something at the highest point, and you see it in terms like acromegaly (enlarged extremities) or acrophobia (fear of heights). Apex/o would point to the apex—the very tip or summit of something—focusing on a single topmost point. Arc/o refers to arc or curvature, not an extremity, and termin/o means end or boundary. So the form that best conveys extremity, top, or an extreme point is acro/o.