I don’t understand please help me

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.

Answer this asap. why did the americans go to china? a. trading b. exploration c. land d. live stock

He resistance of a liquid to flowing is called