Which combining form means pertaining to lips?

• A. Papill/o
• B. Bucc/o
• C. Labi/o
• D. -asthenia

Answer: (C)

This question tests recognizing a combining form that conveys a specific body part and how it combines with a suffix to describe a relation to that part. Labi/o means lip, and when you attach the suffix -al you get labial, which means pertaining to the lips. That makes labi/o the best fit for “pertaining to lips.”

For context, other options relate to different structures or functions: papill/o refers to the nipple or papilla; bucc/o relates to the cheek (buccal), not the lips; and the suffix -asthenia means weakness, which doesn’t indicate a relationship to a body part.