Which combining form means pertaining to protection or exemption from a disease?

• A. Labi/o
• B. Papill/o
• C. Gnath/o
• D. Immune/o

Answer: (D)

Protection from disease is immunity, and the combining form that expresses this idea is immune/o (often seen as immun/o in many terms). This form is used to build words related to the immune system and the body's defense against pathogens, such as immune response, immunology, and immunity. That’s why it denotes protection or exemption from a disease and is the best choice. The other options refer to anatomical structures (lip/labia, nipple/papilla, jaw) and do not convey protection against disease.