Which combining form relates to knowledge (diagnosis)?

• A. lamin/o
• B. gno/o
• C. phot/o
• D. cheil/o

Answer: (B)

Understanding how combining forms carry meaning helps explain why gno/o is the best fit. The idea here is knowledge and knowing, which is the heart of diagnosis. The Greek root gnosis means knowledge, and the combining form gno/o carries that sense, appearing in terms like diagnosis and prognosis—where the goal is to know what the illness is. The other options point to entirely different ideas: lamin/o refers to a thin plate or lamina, phot/o means light, and cheil/o means lip. Since they don’t convey knowledge or diagnosing, they don’t align with the concept tested.