The answer to the first question is the first choice.
The answer to the second question is the third choice.
Because of China's isolation by natural barriers, there was not much trade outside of China, so China's economy was agriculture
The Great Depression was the worst economic downturn in the history of the industrialized world, lasting from 1929 to 1939. It began after the stock market crash of October 1929, which sent Wall Street into a panic and wiped out millions of investors.
Jobs is one of the biggest reasons as to why cities grow and that was a major factor in the 19th century. If there are a lot of jobs available in the cities people are going to move there so they can earn money to support their family or lifestyle
Hopefully this helped and good luck.
Well, there are firefighters also police and others.
