The oropharynx is the part of the throat just behind the mouth. It begins where the oral cavity stops. It includes the base of the tongue (the back third of the tongue), the soft palate (the back part of the roof of the mouth), the tonsils, and the side and back wall of the throat.ral cavity cancer, or just oral cancer, is cancer that starts in the mouth (also called the oral cavity). Oropharyngeal cancer starts in the oropharynx, which is the part of the throat just behind the mouth.
polymorphism - (biology) the existence of two or more forms of individuals within the same animal species (independent of sex differences) biological science, biology - the science that studies living organisms
Allotropy : Existence of an element into more than one physical forms E.g: Coal, lamp black, coke, Diamond, graphite. Allotropy refers to an element, it should be reserved for the different crystalline phases of a given pure element. Polymorphism is a more general term referring also to intermediate phases. Polytypism has a structural meaning: 'Polymorphism' where the polymorphs differ by the stacking sequence of a given type of layers.