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).
Development theory is a conglomeration or a collective vision of theories about how desirable change in society is best achieved. Such theories draw on a variety of social science disciplines and approaches.he theory looks at which aspects of countries are beneficial and which constitute obstacles for economic development. The idea is that development assistance targeted at those particular aspects can lead to modernization of 'traditional' or 'backward' societies.