Answer:
b Gas masks
Explanation:
The use of poisonous gas in the First World War was an important military innovation. The gases used ranged from tear gas to incapacitating agents such as mustard gas and lethal agents such as phosgene. This chemical war was one of the main elements of the first global war and also of the first total war of the 20th century.
The lethal capacity of the gas was limited - only 3% of combat deaths were due to gas - but the proportion of non-lethal casualties was high, with gas becoming one of the most feared factors among soldiers. Unlike most weapons of the time, it was possible to develop effective countermeasures for gas. Hence, in the final phases of the war, although the use of gas increased, in many cases its effectiveness decreased. Due to the widespread use of chemical warfare, in addition to the important advances in the manufacture of high-powered explosives, World War I has sometimes been described as "the war of chemists".
