Of the many new technological innovations and inventions in the late n

Of the many new technological innovations and inventions in the late nineteenth century, which three do you think had the most lasting effect on the American economy?

Explain why you chose these three and indicate the role they played in twentieth-century life.

ANSWER
Consider: telephone; motion picture; phonograph; Bessemer process; incandescent bulb; assembly line process; “system” management; etc.