Final answer:
The Germans introduced submarines, while the British introduced tanks as new military technology during World War I, both having a pivotal role in transforming warfare.
Step-by-step explanation:
During World War I, the Germans introduced submarines as a new military weapon. These were known as U-boats (Unterseeboots) and had a significant impact on naval warfare due to their stealth and ability to sink unsuspecting ships with torpedoes. The introduction of submarines by the Germans and the subsequent Allied countermeasures, like naval escorts and the convoy system, played a crucial role in maritime conflict during the war.
In terms of new military technology introduced by the British, it was the tank that was unveiled in 1916. The early tanks were designed to support infantry and make artillery mobile, potentially ending the deadlock of trench warfare, despite their initial problems with malfunctioning and getting stuck in the mud. Over time, British commanders began to understand the strategic value of tanks on the battlefield.