Chimerism is what happens when cells from one twin are present in the other. For example, white blood cells with Y chromosomes would be found in the female twin. Vigier et. al, 1989.
Piaget's theory of cognitive development. Piaget's theory of cognitive development is a comprehensive theory about the nature and development of human intelligence. It was first created by the Swiss developmental psychologist Jean Piaget (1896â1980).
The family development theory. The family development theory gives me an in site on the changes in the family and how these changes occur in the family life cycle. The theories state that as people progress through various stages and event of the family life cycle they accomplish specific development task.