Which innovation brought the most significant change to farming and ranching techniques in the midwest ?

McCormick Reaper

Explanation:

The innovation that brought the most significant change to farming and ranching techniques in the midwest is known as "McCormick Reaper."

This is evident in how the equipment improved the average farmer's output from two or three acres a day to ten acres a day. It also reduced the amount of human labor and animals used during the harvest period and the techniques of ranching.

The McCormick Reaper was used extensively in Chicago a city in the midwestern region of the United States beginning in 1847.

c. the dred scott v. sandford case,