USA HISTORY

Detailed explanation-1: -Automatic signals, air brakes, and knuckle couplers on the railroads; the Bessemer and then the open-hearth process in the steel mills; the telephone, electric light, and typewriter.

Detailed explanation-2: -The most important inventions in the Second Industrial Revolution include the telegraph, the telephone, the modern lightbulb, the assembly line, the automobile, aircraft, and the construction of the transcontinental railroad in the United States.

Detailed explanation-3: -Among the most influential and far-reaching innovations of the Second Industrial Revolution was the internal combustion engine. First introduced in 1878, it was powered by gas and air, which made it impractical for widespread public use.