In humans,the ...... is a blind sac which hosts some symbiotic microorganisms.

$A$ 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?

The $Crypt$ $of$ $Lieberkuhn$ is an example of:

Crypts of Lieberkühn are located in:

Ammonia is formed during digestion in which of the following?

Assertion $A$: Mammals are heterodont.
Reason $R$: In mammals,permanent teeth replace temporary milk teeth.