The use of hot air balloons for observing the enemy, the invention of the telegraph, the use of the machine gun, development of iron clad ships, submarines, land mines, development and use of railroads for war use, to name but a few
The machine gun changed warfare
I think that was the trench warfare stuff, not sure though.
New inventions changed warfare during World War 1 by creating new weapons and creating more casualties. Some of the inventions during World War 1 were tanks, infantry rifles, and machine guns.
Airpower made killing a mechanical act rather than a personal act.
Do you mean, what invention utilised during the Civil War changed combat? The rifle-barrelled cannon. Or the minie-ball. The post-war invention would have been the machine-gun.
The machine gun changed warfare
nga nga
World War I was dominated by trench warfare for one reason: it was effective in stopping the enemy's attacks. That is to say, defensive technology and tactics were, during this conflict, far more effective than offensive technology and tactics. It would not be until World War II that offensive developments broke through the trench-warfare deadlock.
Nuclear weapons
First specify what you mean by 'then', as you are covering a wide timespan, during which warfare changed radically.
Iron Bridge
Radar
Warfare changed in various ways during ancient times. For example, Roman legions revolutionized warfare through the tactics and formations they used.
The main and most important change brought by technology in the warfare in the 20th century was elimination of the concept of large standing armies during the war. Technology gave birth to the idea of having small elite groups that could reach the warfare in any part of the world.
I think that was the trench warfare stuff, not sure though.
no
Trench Warfare.