The correct answer is:
A) and B).
Mass production allowed weapons to be made faster than ever before, including new ones such as moveable machine guns, choline gas, flamethrowers, zeppelins, and torpedoes. At the same time, vehicles such as tanks, planes, and cars were also mass produced, and trench railways were a military adaptation of the railway technology to the problem of keeping soldiers supplied during the static trench warfare phase of World War I.
Answer:
I believe it is D tell me if I am wrong
I am you provide more information
The Social Structure in the Reconstruction Era was after the Civil War. President Lincoln had a plan to reconstruct the south while the took over big parts of the south.