Federalism or Federal system of government is a political system where two or sometimes more levels of government have the power over the same people and the same land. This shared power is divided between federal government and national and state governments.
IT AFFECTED THEM BY THE WARS WE HAVE FOUGHT WITH THEM
Three ways the railroad helped create modern America are: it made travel easier, stimulated commerce in the economy and increased trade.
If you're asking for just two random explorers, then Meriwether Lewis and William Clark. But im not really sure if thats what youre asking or not...