Cover crop roots hold the soil in place, protecting soil from wind erosion. Cover crops can also protect soil from the impact of heavy rainfall and runoff. Reduced erosion protects and improves water quality by keeping ag chemicals in the ground and out of drainage water.
Answer:
Frederick Jackson Turner argued that overseas expansion was a "safety valve" to keep ambitious Americans content.
this looks like a multiple choice question, but the multiple choice answers are not shown, so this is hard to answer
