Final answer:
Piaget's theory of moral development describes three sequential stages: preconventional, conventional, and postconventional.
Step-by-step explanation:
Piaget's theory of moral development proposes three broad stages of moral development: preconventional, conventional, and postconventional. These stages are sequential and distinct from one another, with movement from one stage to another occurring on a continuum. Piaget believed that morality is developed through cognitive development and interactions with the environment, and it is not solely a biological phenomenon. It's important to note that Piaget's stages of moral development are not explicitly mapped to his stages of cognitive development and do not have widely known unique names.