Who created the famous 'Uncle Sam' character symbolizing the U.S. government?

Thomas Nast

Which animal's tongue can extend longer than its entire body length? Which bird builds nests using saliva instead of twigs or grass In what country can kangaroos naturally be found? The Caucasus Mountains primarily run between the Black Sea and what other sea? What kind of cloud is very high, thin, and wispy, primarily made from ice crystals?