Which prefix meaning dry?

• A. Tympan/o
• B. Xer/o
• C. Aur/o
• D. Arc/o

Answer: (B)

The concept being tested is recognizing a combining form that means dryness. The correct prefix is xer/o-, from Greek xeros meaning dry. It appears in terms like xerostomia (dry mouth) and xerophthalmia (dry eyes), so it directly conveys the idea of dryness in medical terms.

The other prefixes point to different things. Tympan/o- relates to the eardrum (tympanic membrane), as in tympanometry. Aur/o- refers to the ear or ear structures, as in auricle or auditory terms. Arc/o- isn’t a standard dryness-related prefix in medical terminology, and doesn’t convey dryness like xer/o- does.