How many years did Lewis and Clarke explore?

Are there Elves in the US of America? What is the value of a 1949 wheat penny? What is the American constitution? How could ivy baker priest sign 1935 silver certificate? Does pro slavery mean for slavery or against slavery? What was the time period called following the civil war? Who debated the slavery issue with Lincoln? What was Eli Whitney's adulthood? How did racial discrimination effect the lives of negros in the south during that time? What was tarring and feathering about? What is the value of a 1928 US 2 dollar bill with a red seal? What is the value of a 1946 mercury head dime? What was the Red scare like in 1955? What were maximinus' accomplishments? What were William Penn's sacrifices? How do you tell if a 1851 silver dollar is real? First African American millionaire invented black hair products? What events led to the outbreak of the English civil war? What were the different economic lifestyles in both the North and South? Who was the American naval officer negotiated a treaty that opened two Japanese ports to U.S. ships in 1854?