Wayne Dennis Conducted Research with Iranian Orphans Who Spent the First

Wayne Dennis conducted research with Iranian orphans who spent the first two years of life lying flat on their backs. This research provided support for the idea that

A) motor development is primarily influenced by hereditary factors.
B) maturation is necessary but not sufficient for the development of motor function.
C) the extent of stimulation in the environment has no direct impact on the development of motor function.
D) motor development is solely influenced by environmental stimulation.