Explanation : (D) Jean Piaget viewed intellectual growth as a process of adaptation (adjustment) to the world. This happens through three stages:
(i) Assimilation Which is using an existing schema to deal with a new object or situation.
(ii) Accommodation This happens when the existing schema (knowledge) does not work, and needs to be changed to deal with a new object or situation.
(iii) Equilibration This is the force which moves development along.