What is the hardest substance found naturally in the human body?

Tooth enamel

Which utensil did the Pilgrims primarily use during the first Thanksgiving feast? What planet's core is framed by underwater cities inhabited by the Gungans? How many points does a typical snowflake have? What is Loki the God of? What historic speech by Ronald Reagan challenged Soviet Union leadership to demolish a significant Cold War structure in 1987?