Cyrus McCormick developed which agricultural technology?

• A. Mechanical reaper; it replaced scythes as the preferred harvest method.
• B. Steel plow; it allowed deeper soil penetration.
• C. Seed drill; it improved seed placement.
• D. Combine harvester; it integrated threshing.

Answer: (A)

The main idea here is understanding who introduced a key farming machine that transformed harvesting by making it much faster and less labor-intensive. Cyrus McCormick’s development of the mechanical reaper did exactly that: it cut grain quickly and could be powered by horses or mules, letting one worker accomplish what many did with a scythe. This shift from hand-scything to mechanized cutting revolutionized harvest productivity and helped spur the growth of larger farms and westward expansion. That impact—replacing the scythe as the preferred harvest tool—is what makes the mechanical reaper the best answer.

While other technologies are important in agriculture, they address different tasks. The steel plow improved turning over tough soil, the seed drill helped plant seeds more accurately, and the combine harvester (which came later) adds threshing to harvest. None of these specifically capture the moment of replacing scythes with a machine designed to harvest grain quickly, which is why the mechanical reaper is the correct choice.