As with most locations for settlements in any civilization the key factor is settlements were located in the lowlands where the land was fertile and could be farmed. Geography is very important when a site is picked for settlement. The site must be able to support human activity.
The United States first began developing nuclear weapons in 1939, during World War II, under the order of President Franklin Roosevelt. Motivation was the fear that US was engaged in a race with Nazi Germany to develop nuclear weapon. This project is best known as Manhattan Project.
Answer
The Zimmerman note finally turned the eyes of the American public towards declaring war on Germany, they finally snapped after Germany's attacks on a American ships.
Its A or D hope this helps
His Expedition went through Texas, Oklahoma, and Kansas
