Which of the following was the economist who believed the government should "prime the pump" by spending more in the economy when the economy slows down? a. Adam Smith
b. Milton Friedman
c. John Maynard Keynes
d. Stephen Levitt

The best answer to go with is b

The changes to agriculture in the united states since 1900 is that increased mechanization has increased food production, thereby increasing the need for labor. there has been an increased need for higher speeds of food production due the fact that the population in the united states continues to rise.