What fuels America?

Before starting out, I would have answered "Dunkin Donuts" (It's a joke...). Then as we drove on, I would have said McDonalds. From Michigan, through Indiana, Illinois, and most of Wisconsin, there is a McDonalds at every exit on the interstate. However, by western Wisconsin, and into Minnesota, then SD, this changed and they became much, much fewer. It may have something to do with the rural nature and the largely farming communities in Minnesota and SD.

The answer as far as I can tell is Corn. From when we left Chicago, 80% of the crops being farmed is corn. Corn, corn, corn as far as we can see. Even in SD, which is flat as a pancake, and where you can truly see to the horizon, all you can see is corn.