Which combining form is used to describe dryness in terms like xerosis?

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

Answer: (B)

The idea here is that medical terms use combining forms from Greek or Latin to convey a specific meaning. For dryness, the root is xer/o, coming from the Greek xeros meaning dry. When you attach a suffix such as -osis, you form xerosis, which describes the condition of being dry. This same combining form appears in related terms like xerostomia (dry mouth) and xerophthalmia (dry eye). The other roots point to unrelated ideas: isch/o means to suppress or hold back, aur/o relates to the ear, and tympan/o refers to the eardrum. None of those convey dryness, so xer/o is the correct combining form.