$A$ 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?

In which organ,besides longitudinal and circular muscles,are oblique muscles also present?

Both the crown and root of a tooth are covered by a layer of bony hard substance called:

What are digestive organs? Describe the various parts of the human digestive system.

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.

Explain the structure of the mouth.