[originaltext] What was the most popular mix about the United States in the

What was the most popular mix about the United States in the 19th century was that of the free life of the farmer. It was said that the farmers worked hard on their own land to produce whatever their families needed. They might sometimes trade with their neighbors, but in general they could get along just fine by relying on themselves, not on commercial ties with others. This is how Thomas Jefferson idealized the farmers at the beginning of the 19th century. But by the mid-century, sweeping changes in agriculture were well under way as farmers began to specialize in the raising of crops such as corn or wheat. By late in the century, revolutionary inventions in farm machinery had vastly increased the production of specialized crops and extensive network of railroads had linked farmers throughout the country to markets in the east and even overseas. By raising and selling specialized crops, farmers could afford more and more finer goods and achieve much higher standards of living. Now farmers were no longer dependent just on the weather and their own efforts, their lives were increasingly controlled by the banks, which had power to grant or deny loans for new machinery, and by the railroads which set the rates for shipping their crops to the market. As businessmen, farmers now had to worry about national economic depression and the implement of world supply and demand on, for example, the price of wheat in hands. And so by the end of the 19th century, the era Jefferson’s independent farmer had come to a close.
20. What does the passage mainly talk about?
21. What was the major change in agriculture during the 19th century?
22. What was one result of the increased use of machinery on farms?