chlorine
Trench warfare was one type, and one which was used more than it had been in any previous war (and maybe since then). Also, things such as gas attacks are classed as well as use of tanks to invade enemy territory and fighter planes.
Tanks Poison Gas Germ Warfare
There were a few better techniques due to technological advantage, one was trench warfare, gas warfare, the invention of machine guns, grenades, and artillery
Gas masks are used to protect people especially soldiers when gases are used in warfare or domestic disturbances. They were used in World War I to protect soldiers against mustard gas.
Gas masks were developed to protect from the new gas warfare. Widespread use of trenches. Neither was terribly effective.
Chlorine gas has a yellowish-green appearance. As relates to warfare and WW1 chlorine gas was first used by the Germans against French troops in the second battle of Ypes, 1914.
The invention of machine guns, gas warfare and trench warfare
Chlorine gas is yellowish green. It's a yellowish white when a solid.
Warfare using mustard gas and chlorine gas.
chlorine
Yes, it's a yellowish-green gas.
The gas itself is yellowish-green, so ....
chemical warfare was prevalent , later outlawed by the Geneva convention
Chlorine gas is yellowish green! Bromine gas is brownish orange.
Chlorine gas is a yellow-green kind of color.
Gas warfare would have been the warfare conducted by using poisonous gas to clear out trenches during WW1, but even during WW1 when gas was the most common, it still wasn't used excessively as it was viewed as an evil way to fight.
Under standard conditions of temperature and pressure Fluorine is a yellowish brown gas.