Desertification Can Occur from Over Grazing and Over Use of Ground

Desertification can occur from over grazing and over use of ground water.An example was the dust bowl during the 1930s in parts of the Great Plains of the United States.Which of the following could best explain this observation?

A) Deserts only form when rainfall levels drop for hundreds of years
B) Desert plants don't need water to survive
C) Desert plants cannot be eaten by herbivores
D) When grassland plants become dry herbivores will no longer eat them
E) Grassland plants cannot survive if water levels drop