Which of these military product innovations first appeared on the battlefield during World War I and fundamentally changed land warfare for the next century?

Throughout military history, certain product innovations have completely transformed battlefield tactics and strategy. The development of new weapons, vehicles, and defense systems has often determined the outcome of conflicts and shaped geopolitical power. This trivia question focuses on a revolutionary product that fundamentally altered modern warfare capabilities. Test your knowledge of military technological history and the products that made nations into superpowers.

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The military tank (first deployed by British forces at the Battle of the Somme in 1916)
The assault rifle (while early designs existed, the modern assault rifle wasn't widely used until WWII)
Guided missiles (primitive guidance systems were tested but not deployed in combat until WWII)
Military drones (early unmanned aerial vehicles were experimental only until decades later)