What is the most common fossil fuel to the US?

Are individual rights and liberties adequately protected by the US Constitution? Was the blackfoot tribe hunters or farmers? What is the value of a 1920 US 1 dollar bill? Was John Dillinger a Native American Indian? What caused conflict with the union pacific railroad? Who begins a war? Who was the first seceratary of the treasury of the US? What act gave land to homesteaders if they lived on it for five years? What resources were in the Mexican cession? What was the main goal of the north before the civil war? Do a 1941 penny value any money? How much does a 1 dollar silvercertificate from 1957 b worth? What is the value of one penny coin pre 1770? When did France empancipate all of its slaves? How much is a 1910 Quarter Eagle coin worth? What did the headright system do? What is the Current value of 1917 wheat penny? How did Lincoln weaken the Confederacy? In 1713 France owned most of what part of North America? What was the date of the Olive Branch Petition?