Which innovations in the 2nd industrial revolution transformed the nature of economic activity in the US?

The Second Industrial Revolution, occurring from the late 19th to early 20th centuries, introduced key innovations such as electricity, the internal combustion engine, and advancements in communication like the telegraph and telephone. These technologies facilitated mass production, increased efficiency in manufacturing, and enhanced transportation networks, significantly reshaping economic activities. The rise of factories and urbanization led to the growth of consumer markets and a shift toward a more interconnected national and global economy. Overall, these innovations transformed the U.S. from an agrarian society to an industrial powerhouse.