Researchers at the Malpai Borderlands in Southern New Mexico and Arizona

Researchers at the Malpai Borderlands in southern New Mexico and Arizona have found evidence that __________________.

A) the region cannot sustain any level of commercial ranching
B) ranchers have been planting mesquite to replace lost grasslands
C) ancient nomadic tribes permanently altered the landscape by settling down and ranching in one area
D) fire suppression has played a major role in the degradation of the rangeland in the area
E) desertification has resulted in soil compaction and erosion