Cattle Grazing Has a Surprisingly Harmful Affect on Dry Grassland

Multiple Choice

Cattle grazing has a surprisingly harmful affect on dry grassland of the southwestern United States.What aspect of grazing is most likely responsible?

A) Cattle are seed-dispersal mutualists; they gather shrub seeds while grazing and then deposit them in a concentrated area when they defecate.
B) Cattle compress the soil; the small amount of rainfall runs off the surface rather than penetrating, and the deep-rooted grasses are replaced by shallow-rooted shrubs.
C) Cattle droppings are toxic to the grasses that cattle prefer; eventually, the buildup of toxins permits only toxin-resistant shrubs to grow.
D) Grazing exposes the native plants to sunlight, which initially stunts and eventually inhibits their growth.