Both the crown and root of a tooth is covered by a layer of bony hard substance called
a)	Enamel	b)	Dentine	c)	Bony socket	d)	Cement

(a)

Each teeth is distinguishable into crown, neck and root. The crown is covered over by a thick layer of enamel, which is bluish white and hardest substance in body. The remaining part of tooth is covered by a thin layer of yellowish bone like cement. Beneath the enamel and cement, the main part of a tooth is formed of a thick layer of less hard and somewhat elastic dentine.