Answer: D. i., ii., and iii.
All three of these actions have caused desertification in Africa. Overgrazing is a problem, especially in communities that practice animal husbandry intensely. The second problem, that of farming the same land over and over, is particularly complicated by the fact that many communities do not rotate crops. Finally, deforestation is a significant problem not only due to the cutting of trees, but to the problems of runoff and erosion that deforestation causes.
