I'm not sure 100% what exactly this question is asking, but I know World War 1 was the first war to include Gas masks and Chemical warfare, so that is more than likely the answer.
The US became involved in WWII due to the Pearl Harbor attack by the Japanese.
Answer:
was under the control of austria
Explanation:
Answer: i cant find the answer :( srry
Explanation:
C and D maybe A but I'm not that sure