The answer is content as content is the one responsible of having to show what the imagery or the work of art is about. Is a way of having to express the subject matter and to depict the portrait that is being displayed as an art for viewers to see and define it in ways that they could understand.
The answer is, Pottery<span> is one of the oldest materials for sculpture, as well as clay being the medium in which many sculptures cast in </span>metal<span> are originally modelled for casting.</span>