China instituted a one-child policy in 1979 because the government recognized that the country is the most populated in the world. major cities were suffering from overcrowding. the large aging population was draining the economy.

The transcontinental railroad provided a means of fast transportation. it cut a 6 month trip into 6 days, created jobs for many people and encouraged immigration. the homestead act played a huge role in western expansion; it allowed settlers to begin a fresh start, and gave them land in exchange for their residence for up to five years and a small fee.