Answer:
2. new technology and a system of railroads.
Explanation:
The gilded age is the name of the period at the end of the 19th century. This age is characterized by rapid industrialization.
After Transcontinental Railroad was finished, the larger parts of the US were able to be settled and the goods could be transported more easily. This change also helped with many economic changes. However, much of the wealth went to already rich people and not the workers.
The urbanization that was partly made possible by railroads helped also the progression of technology. With this, many engineering advances were made - bridges, canals, trolleys, and subways, but also hard industry and coal mines.
Because of this brisk change of life into the urban areas full of technology and the open possibility of transport, gilded age is the time of the second industrialization and rapid economic change.
