Warfare during world war 1 was deadlier than past wars. Which of the following is not a reason?
A. New technology
B. stalemate was created
C. use of airplanes
D. new leadership

Will mark as brainliest. i need .select the correct boxes. 1. similarity between united states and roman republic. 2. difference between united states and roman republic1. the government had a written constitution. 2. women could vote. 3. there was a system of checks and balances. 4. the government could use a veto to cancel an action.