What combining form means 'smooth'?

• A. Caud/o
• B. Lei/o
• C. Amyl/o
• D. Lact/o

Answer: (B)

This question tests recognizing the combining form that describes texture or tissue type, specifically “smooth.” The combining form lei/o means smooth, derived from Greek leios. It appears in terms like leiomyoma, a tumor of smooth muscle, and leiomyosarcoma, a malignant tumor of smooth muscle. The other options refer to unrelated ideas: caud/o means tail, amyl/o means starch, and lact/o means milk. So lei/o is the correct combining form for “smooth.”