How did the transcontinental railroad affect us commerce?

The Transcontinental Railroad was a railroad line through the United States that united the city of Omaha, Nebraska, with Sacramento in the 1860s, thus uniting the Eastern rail network of the United States with California, on the Pacific coast.

It ended with the famous Golden Spike ceremony held on May 10, 1869 in Promontory, Utah, creating a nationwide mechanized transportation network that revolutionized the population and economy of the American West.

This railroad was considered the greatest American technological achievement of the 19th century. It served as a vital link for industry, commerce and travel, uniting the East and West halves of the United States, and creating new settlements in the West.

the answer is a. laws were enacted in the aftermath of the plot to make it harder to free slaves,increasing sectionalism