What was the connection between the gadsden purchase and the southern railroad route?

The Gadsden Purchase was a transaction that followed the conquest of much of northern Mexico by the United States. Its relationship to the transcontinental railroad is that  it was purchased because it was the most practical route  for the transcontinental railroad.  The purchase was negotiated by the U.S. minister to Mexico, James Gadsden.

for the 2 countries u can do china and america because america has a democratic government while china has a communist government.

a democracy is a government run by the people either by directly voting or indirectly by electing representatives. an oligarchy is a government run by a few or a small group of people. a democracy and oligarchy are similar because both in an oligarchy and an indirect democracy, a small group of induvial determine the laws for a large group of people they are different because in an oligarchy it is easier to control and they do not have to answer to a large number of people in the country, unlike a democracy where they do have to answer to a large number of people an county that is a democracy would be the united states. a country that is an oligarchy would be the china.