Final answer:
The end of the Civil War and the Homestead Act were key in reuniting the U.S. and furthering western expansion. The Louisiana Purchase significantly increased the nation's territory, and the transcontinental railroad connected the coasts and supported industrial growth.
Step-by-step explanation:
The United States experienced several significant events that brought different regions together and fueled western expansion. The end of the Civil War was a critical event in reuniting the nation and setting the stage for future growth. To help Americans fulfill the goal of western expansion, the U.S. government passed the Homestead Act, an action that allowed individuals to claim land in the west to encourage settlement and development.
Moreover, the importance of the Louisiana Purchase cannot be overstated, as it doubled the nation's size and provided immense opportunities for westward expansion. The construction of the transcontinental railroad further united the country by providing a continuous rail link from the Atlantic to the Pacific, fostering rapid industrial development and helping to transport vast mineral resources from the western states.