Answer:
resulted in an increase in both international and domestic trade of goods and services throughout the United States
Explanation:
Following the construction of railroads during this period, railroads provide economical means of transportation of raw materials, equipment, and commodities, from west to east, and north to south of the United States. Thereby goods are easily transported to point of sales in the country and shipping point for export to overseas.
Similarly, it aids the transportation of import goods to various parts of the country.
Hence, The expansion of the North American railway and transportation system in the second half of the nineteenth century "resulted in an increase in both international and domestic trade of goods and services throughout the United States."