If neither the subjects nor the people working with the subjects know which group theyare in,

The development of the sociocultural theory is attributed to

a) Skinner. b) Bandura. c) Vygotsky. d) Bronfenbrenner.

What is the cause of phenylketonuria?

a) rubella virus b) air-borne toxins c) a gene mutation d) excess levels of neurotransmitters