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

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

Answer: (C)

Extremity or top is conveyed by the combining form acro/o. It comes from Greek akros meaning topmost or outermost, and it appears in terms describing the farthest outward part of a limb or the uppermost point of a structure, such as acrocyanosis (bluish extremities) and acromegaly (enlarged extremities). This makes acro/o the best match for extremity, top, or extreme point. The other options describe different ideas: arc/o denotes arch or bow; termin/o means end or boundary; apex/o refers to the apex or tip, which is a more specific top rather than the general sense of extremities.