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).
Family Development Theory. n Family Development theory is an interdisciplinary approach of examining the family. n Involves biological, social, and psychological perspectives of development. Biological. n Biological needs in a family vary depending on the family structure and ages of its members.