Ancient Greece and ancient Rome
Explanation: quickest answer
It was a very deadly war--the Great War produced new forms of guns, bombs, and gas weapons which proved to be devastating.
The Great War, World War I, saw the emergence of tanks, rapid fire machine guns, grenades, mustard gas, and well as airplanes. The method of trench warfare in addition to highly accurate and deadly weapons led to both large numbers of causalities and stalemates. These weapons made it difficult to move position causing need for new techniques or new technology to allow movement.
The answer is D. All of the above
Emperor Constantine made the religion, Christianity, a new, legal religion in the Roman Empire.
