Pertaining to the tongue?

• A. Lingu/o
• B. Lith/o
• C. Glyc/o
• D. Hidr/o

Answer: (A)

The main idea here is how medical terms build meanings from combining forms. Lingu/o is the combining form that means tongue. When you see a term formed with lingu/o plus a suffix like -al, it gives you “pertaining to the tongue” (as in lingual). The other roots point to different things—lith/o means stone, glyc/o means sugar, and hidr/o relates to moisture or sweat—so they don’t convey anything about the tongue. That’s why lingu/o is the correct choice for “pertaining to the tongue.”