The expansion of the railroad directly led to economic growth in the us because
railroads increased competition between different industries.
railroads allowed company owners to travel all over the country.
railroads made resources and products easier to transport.
railroads led to increased prices of newly available products and resources.

railroads made resources and products easier to transport

Explanation:

The establishing of the railroads across the Untied States was revolutionary, and it managed to prompt a rapid development of numerous industries, thus a boom in the economy. The railroads made it possible for the resources to be transported over long distances, as well as the manufactured goods. Not that it was possible to transport them over long distances, but it was also much cheaper and much faster.

the answer is "focused on"

lol gave an answer 1 week that's the answer for those who need it in the future xd

to keep us neatruel and not get involved in any wars

he assumed control of treaty negotiations with a hostile power