Which combining form pertains to night and darkness?

• A. Noct/i
• B. Rhin/o
• C. Pyr/o
• D. Geront/o

Answer: (A)

Recognizing the combining form that means night is the key idea here. noct/i is the form that denotes night or darkness, with the i serving as the linking vowel when a suffix is added. This makes noct/i the correct choice for terms related to nighttime or darkness. In contrast, rhin/o refers to the nose, pyr/o to fever or fire, and geront/o to old age, so they don’t fit the meaning of night.