What was one of the main new technologies used in World War I?

Submarines were one of the main new technologies used in World War I, particularly by the Germans, who utilized them in their naval warfare strategy. These submarines, known as U-boats, played a critical role in disrupting Allied shipping and targeting military and commercial vessels. Their ability to operate stealthily underwater allowed them to pose a significant threat and changed naval engagements dramatically during the war.

In contrast, jet-propelled airplanes were not developed until after World War I; the technology for powered flight was still in its infancy, and most aircraft used during the war were propeller-driven. Television was not utilized during the war as it had yet to become a viable technology; its development came much later. While automobiles were indeed used during World War I, they were not new technologies in the same sense as submarines, as automobiles had already been in use for several years prior to the war. Thus, submarines stand out as a revolutionary advancement in military technology during World War I.