300
Give 1 of the "firsts" that took place during WWI and how it affected the war effort...
What is 1. gas masks (allowed troops to survive poisonous gas) 2. widespread use of machine guns (higher death tolls) 3. tanks (allow people to hide behind/drive through "no man's land") 4. submarines (Germans sank Allied boats) 5. chlorine/mustard gas (poison enemy from far away) 6. trench warfare (allowed men to stay below ground/hidden)