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Science across the curriculum.0:01
Exercise 2B, page 116 A tooth has two main parts.0:04
The crown is the part you can see, and the root is the unseen part that is below the gum and fastens the tooth in the jawbone.0:25
The outer part of the tooth and the hardest substance in the body is enamel.0:33
Underneath this is a layer of dentin, which is softer than enamel but similar to bone.0:38
In the middle of the tooth is the pulp.0:43
This contains cells, blood vessels, and the nerve of the tooth, and is protected by a layer called cementum which covers the root and keeps the tooth securely attached in the gum SA.0:46
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