The population of the Chaco Canyon in New Mexico changed significantly between the tenth and eleventh centuries, as evidenced by the remains of its great houses. A. Before the 1970s, scholars believed that the fail of Chacoan society was caused by farmers' cutting down all the trees to build their great houses. B. After discovering trails connecting Chaco to surrounding communities, scholars came to believe that there were many forested oases to support those communities. C. Archaeological evidence has led current scholars to believe that Chaco was a religious center during the Bonito phase. D. Archaeological findings indicate that Chaco Canyon was completely abandoned by the end of the thirteenth century. E. Researchers' findings in the 1980s revealed that Chaco Canyon had been a fertile agricultural area that caused the population near the center of the canyon to increase steadily during the Bonito phase. F. Recent geological studies indicating the presence of water in Chaco Canyon in the eleventh century may alter scholars' belief that the area was not favorable for farming.