The water content in enamel is approximately .......

$A-$ The permanent teeth begin to replace the temporary ones at about the age of six years.
$R-$ This type of dentition is called diphyodont.

The hardest substance of the tooth is .......

Which of the following vitamins is synthesized by bacteria in the animal body?

In humans, the length of the alimentary canal is about (in $\text{ feet}$)

Which of the following terms describes human dentition?