The outermost layer of an alimentary canal is known as

Which layer of cells secretes the enamel of the teeth?

In the colon, the construction of its wall forms a series of small packets called:

The diagram given below depicts the human digestive system. Label it from $A$ to $F$ and choose the correct option accordingly.

Given below are two statements.
Statement $I$: Since human beings have different kinds of teeth fitted in two jaws,the dentition is described as diphyodont.
Statement $II$: Human beings have four different kinds of teeth,hence it is described as heterodont.

$A$ baby boy aged two years is admitted to play school and undergoes a dental check-up. The dentist observed that the boy had twenty teeth. Which teeth were absent?