The hardest substance present in the human body is:

Select the correct statement$(s)$:
$(A)$ The alimentary canal begins with an anterior opening,the mouth.
$(B)$ Each tooth is embedded in a socket of jaw bone.
$(C)$ Humans exhibit a diphyodont type of dentition.
$(D)$ The oesophagus and the trachea open into the larynx.

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

What is the correct sequence of the parts of the small intestine?

Which of the following parts of the digestive system does not secrete any digestive enzyme?

The posterior part of the soft palate hangs down into the pharynx as a small,finger-like projection called the .......