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tooth enamil I believe enamel is the hard, outer covering of a tooth. The soft inner tissue is called pulp.
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It's called a bridge.
The hard surfce on the surface of a tooth is enamel.
It is called the cementum and it's the third hardest substance in the human body, after the enamel and the dentin.
The hard covering of a seed is called the seed coat. It serves to protect the seed from damage, dehydration, and pathogens.
The shell.
exoskeleton
The outer covering of the grain is called Husk.
The hard external covering of insects is made of a substance called chitin.
It is called the enamel. It's the most external layer of a tooth and the hardest substance in the body.
The section of the tooth where the anatomical crown meets the anatomical root is called the cementoenamel junction (CEJ). This junction marks the transition between the enamel covering the crown and the cementum covering the root.