If you were a specialist working for the national security agency, your main job would likely be a. creating coded messages. b. electronic surveillance. c. fixing spy satellites. d. working in the field to carry out covert operations.

The correct answer is D

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.