Answer:
Heavy artillery, machine guns, tanks, motorized transport vehicles, high explosives, chemical weapons, airplanes, field radios and telephones, aerial reconnaissance cameras, and rapidly advancing medical technology and science were just a few of the areas that reshaped twentieth century warfare.
Observing a day of rest one day a week
Answer:The Battle of Gettysburg
Explanation: Gettysburg was a watershed moment in the Civil War, with the Union losing 23,000 men killed, wounded, or missing in action.
I hope that explains it