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

The opening of the common bile duct is guarded by which sphincter?

The pulp cavity of the tooth is lined by .......

$A-$ 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 function of the tongue is to

Where do certain symbiotic microorganisms normally occur in the human body?