<span>A major reason why the United States government spent money to improve the National Highway System was that the infrastructure was crumbling and became dangerous for drivers.
Hope this helps!</span>
One way in which Americans developed a unique cultural identity after the Revolution was by ratifying the Constitution, which created a true "nation" as opposed to a lose confederation of states, which allowed people to develop a sense of nationalism and "pride" in their country.
Assuming your subject of the question is when we were trading with primarily African countries and Britain for goods we traded mostly animals, crops, cotton, and received the same in return for the most part (except cotton)
Also we traded for and in return of slaves
