What explains the United States rise to the industrial and economic importance in the late nineteenth century?

the railroad industry led to the development of other processes.

Explanation:

Having refrigerated train cars allowed meats to distributed throughout America, allowing the agricultural economy to benefit, ultimately enabling the US to profit. It also created a whole new industry, creating more jobs in certain cities. Those cities had to create housing etc to accommodate the influx of people coming in for jobs.

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it was the first amendment