SAT Subject US History Practice Question 833: Answer and Explanation
4. The mechanical reaper, invented by Cyrus McCormick in the 1830s, was most significant because it
A. turned over the hard prairie soil.
B. planted seeds four times as fast as a man could do by hand.
C. aided irrigation of the arid Midwest.
D. increased cotton production.
E. cut wheat at a greater rate than the scythe.
Correct Answer: E
The mechanical reaper cut wheat by using horse power and rotating blades, resulting in a twelve-fold increase in production. The steel plow, invented by John Deere, turned over soil (A). The reaper did not plant seeds (B) and did not aid in the irrigation of the Midwest (C). The cotton gin, invented by Eli Whitney in 1793, led to increased cotton production (D). Mechanical harvesting of cotton developed in the middle of the 20th century.