What effect did the use of trenches and new technologies during World War I have?

Trench warfare exposed soldiers to prolonged fighting, while new weapons such as machine guns, artillery, and poison gas could kill large numbers at once. Together, these changes made World War I much deadlier than many earlier wars and caused enormous casualties. The correct choice is “Warfare was far deadlier than in the past and resulted in enormous casualties.”

AI-written and checked against the verified answer.