After the completion of the railroad, a major industry in the west
a. ranching
b. banking
c. milling
d. fishing

The correct answer is ranching.

The development of the Transcontinental Railroad allowed for a massive increase in population in the West. This is due to the fact that the railroad system allowed for cheaper and faster travel.

When settling in the West, farmers began working on ranches. This ranching include raising cattle and growing crops. Thanks to the railroad, western farmers had the opportunity to sell their goods to national markets. This was a drastic change in American society, as before this time markets were often small and local.

answer; i believe the correct answer is prefrontal cortex;