Explain the terms heterodont, thecodont,  and diphyodont.

Heterodont : It is the condition of having different types of teeth. For example humans have four different types of teeth namely incisors, canines, molars and premolars. 

Thecodont : The type of attachment in which each tooth in embedded in a socket. 

Diphyodont : The type of dentition characterised by two sets of teeth. First set is of temporary and second is of permanent.