Which statement about enamel and dentin is correct?

• A. Enamel lies above dentin and is mineralized; dentin beneath contains tubules and is sensitive.
• B. Dentin lies above enamel.
• C. Enamel is soft; dentin is hard.
• D. Dentin has no tubules.

Answer: (A)

Enamel forms the outermost, highly mineralized layer of the tooth crown, sitting on top of dentin and built to be incredibly hard. Beneath it lies dentin, a softer, porous tissue that contains microscopic tubules extending toward the pulp. Those tubules carry sensations to nerve fibers, so dentin is sensitive when exposed. That combination—enamel on top, mineralized and hard, and dentin below with tubules and sensitivity—is why the statement is correct. The other options are inconsistent with tooth anatomy: dentin does not lie above enamel, enamel is not soft, and dentin does have tubules.