Correct. The answer is c. In between bursts of horrific violence, soldiers experienced long periods of boredom and discomfort during which they spent most of their time repairing their defenses and keeping an eye out for a potential enemy assault.

Incorrect. The answer is c. In between bursts of horrific violence, soldiers experienced long periods of boredom and discomfort during which they spent most of their time repairing their defenses and keeping an eye out for a potential enemy assault.

Correct. The answer is d. Antiquated military strategies that emphasized the frontal attack were rendered obsolete by the machine gun, barbed wire, long-range artillery, and poisonous gas.

Incorrect. The answer is d. Antiquated military strategies that emphasized the frontal attack were rendered obsolete by the machine gun, barbed wire, long-range artillery, and poisonous gas.

Correct. The answer is d. Another 21 million were wounded.

Incorrect. The answer is d. Another 21 million were wounded.