Concept:Soil erosion is caused by activities that leave the soil bare; conservation methods are not causes.Explanation:Deforestation removes the tree cover and exposes the topsoil to wind and water.Overgrazing destroys the grass layer and loosens the soil.Bush burning kills soil organisms and removes protective cover.Afforestation is a soil conservation measure, not a cause of erosion.Therefore, the possible causes are I, II, and IV only.Answer:B. I, II, and IV only