China was the largest economy for centuries because everyone had the same type of economy—

subsistence—and so the country with the most people would be economically biggest.

Then the Industrial Revolution sent the West on a more prosperous path. Now the world is returning to a common economy, this time technology- and information-based, so once again population triumphs.

a. Why was China the world’s largest economy until 1890?

b. Why did the United States surpass China in 1890 to become the world’s largest economy?