3. which new type of warfare was responsible for civilization and military deaths and was banned after the war?

and does anyone have the rest of theses

This is probably biological warfare because it's not allowed according to the Geneva congress. Using poisons, toxic matters, viruses and bacteria, as well as flamethrowers and things like that are forbidden or else it will be considered a war crime and people will answer for it. It was practiced in World War 1 but was forbidden after.