Answer:
Herds have to be driven from place to place to find food and water. Generally, cattle fed valleys and open range while sheep feed higher in mountains, causing over grazing at all altitude levels. As mature grasses become scarce, cattle and sheep eat new grass before it produces seed. Hooves of both animals destroy root systems and their trampling hardens the soil so grass seedlings could not survive. Water holes became large mud holes where no grasses grew and the land could no longer capture and store water. Grassland was replaced by scrub grass and sagebrush. With grasses gone, the range climate becomes hot and arid.
Explanation:
