What is the answer to all of them !? HELP ME please

In a economy individuals answer the three basic and the central authority or leaders have little say in the economy.

Which of the following statements best characterizes changes to agriculture in the united states since 1900? a. increased mechanization has reduced the need for labor. b. increased mechanization has increased the need for water, thereby increasing the need for labor. increased mechanization has increased the use of land, thereby increasing the need for labor. d. increased mechanization has increased food production, thereby increasing the need for labor. select the best answer from the choices provided.

Scientists think that convection currents flow in earth’s a. continents. b. mantle. c. lithosphere. d. inner core.