Which combining form pertains to aging; old age?

• A. Noct/i
• B. Dent/i
• C. Proxim/o
• D. Geront/o

Answer: (D)

This question tests knowledge of combining forms that denote aging. The combining form geront/o means aging or old age, which is seen in terms like gerontology (the study of aging) and geriatric (related to aging or elderly people). The other roots point to different concepts: noct/i means night, dent/i relates to teeth, and proxim/o refers to near or close. Because geront/o specifically conveys old age, it is the correct form for aging.