Andean agriculture is complex and dynamic, and traditional practices continue not as cultural survivals but as rational choice. The success of Andean people in creating stable productive systems and building a great civilization has been the subject of anthropological and geographic research, which has described the general cultural history of the area and delineated the major responses to its physical, ecological and economic stresses. The Andean physical environment is characterized by great diversity that creates many opportunities but also frequent stresses. Andean agriculture has responded to its physical and social environment in three ways: through diversity, production zone organization, and community and individual control. The complexity of traditional Andean agriculture compounds the theoretical and methodological difficulty of studying the environmental impact of economic and technological change. Traditional adaptations to the Andean environment have been affected by commercialization that typifies economic change in the region.