Archaeologist Time Kohler has attempted to explain why villages and areas in the southwestern part of the United States were abandoned around A.D. 900. A. Kohler attributes the immediate cause of the abandonment to problems with corn production at a high altitude during short growing seasons. B. Kohler maintains that the Anasazi's transition to living together in villages was a key factor in the process of the degradation of the environment. C. The development of intensive agricultural methods depleted the soil and resource management strategies made it difficult to cope with poor growing seasons. D. Kohler's research indicates that in addition to agriculture, the Anasazi lived on the pinon nuts they grew and the animals they hunted in the area. E. Increases in seeds from pioneer plants and systematic changes in the animals hunted and the trees used for construction and fuel are evidence of environmental degradation. F. The dependence of the Anasazi on food supplies from nearby villages with better systems of water control and food storage facilities resulted in the Anasazi abandoning the larger villages.