Which president made the Louisiana Purchase in 1803?

Which Vice President became president after Zachary Taylor died in 1850? Which Vice President became president after James Garfield was assassinated? Which president wrote the Declaration of Independence? Which president is known as the "Father of the Constitution"? Which president sent Lewis and Clark on their expedition? Which president issued the doctrine warning Europe against new colonization in the Americas? Which president signed the Indian Removal Act of 1830, leading to the Trail of Tears? Which president led the U.S. during the Mexican-American War?