Answer:
New technology and a system of railroads.
Step-by-step explanation:
The United States in the later phase of the 19th century witnessed the emergence of the Gilded Age. Technological inventions and developments drastically enhanced the course of history. Devices such as incandescent light bulbs and the Bessemer Process greatly influenced development in America. Moreover, the development of the "Transcontinental Railroad" made the trade easier than earlier.