Explanation:
much of the knowledge written on them may have disappeared
They are established as outlined by a state’s constitution.
The G.I. Bill is a law passed in June 1944 in the United States, to provide a legal mechanism that would allow the demobilized soldiers of World War II to access funds for technical or university studies, as well as a pension that would help to their subsistence by one year. This norm also gave the soldiers facilities to get loans to buy homes or start a business on their own.
According to the statement above: "These explorers ventured into the Louisiana Territory in 1803 and became the first U.S. citizens to navigate their way westward to the Pacific Ocean."
The answer is: Louisiana Purchase.
Hope this helps.
They got to do what they could not do before