Tooth enamel develops in layers over time, creating a pattern of rings like tree rings that bear indications of age, diet, health and even environmental changes. The concentric rings are called Retzius lines, or striae of Retzius, named for Anders A. Retzius, the Swedish anatomist who studied and wrote about them in the 1830s.
Which mythological figure was known to carry a trident?
Previous answer: Daniel Webster wages a court battle against the devil in a short story by Stephen Vincent Benet.
TRIVIA FANS: Leslie Elman is the author of "Weird But True: 200 Astounding, Outrageous and Totally Off the Wall Facts." Contact her at [email protected]