Concept:The hardest part of the tooth is the protective outer layer called enamel.
Explanation:Enamel is the hard, white outer layer that covers the crown of the tooth.
It is highly mineralised and contains mainly calcium phosphate (
Ca3(PO4)2) arranged as hydroxyapatite crystals.
This mineral-rich structure makes enamel the hardest substance in the human body.
Because of its hardness, enamel can withstand the strong forces of biting and chewing without wearing away easily.
Dentine lies beneath the enamel and is not as hard.
Cement covers the root of the tooth, while pulp is the soft inner tissue containing nerves and blood vessels.
Therefore, enamel is the hardest part of the tooth among the given options.
Answer:A. enamel.
