The US and the Soviet Union
The earliest Chinese people did not have to worry about invasions from foreign countries because of their strong army and geography. The Chinese army present in ancient times were very strong and able to defend their lands. Chinese also build china wall in order to protect their lands from the invasion of other people. The geography of china also made difficult for the invaders to capture china.
The most important reason was economical: slavery was profitable for slave owners in the South, and they were against its abolishing. The southern plantations were very work -intensive, so a lot of work was needed and slave labour was a very cheap source of labour that the owners didn't want to give up upon.
the correct answer is <span>B. The Southern plantation economy depended on slavery. </span>