Why did the incan rulers build their network of roads?

Under president reagan, the united states began to develop the strategic defense initiative, nicknamed "star wars.” what was the goal of that plan?

Which combination would the president most likely use to convince congress to pass an economic stimulus bill?

Between 1820 and 1860, the united states received a huge number of immigrants from european nations. on the map, identify the state where the most immigrants moved in search of jobs.