How does mass production and industry transform war?​

For the Allies in particular, the production of tanks, airplanes, ambulances and munitions sped up dramatically thanks to the implementation of the assembly line.

When the U.S. entered the war, it brought with it much-needed manpower and the means of mass production. The U.S. government enlisted auto manufacturers to help crank out airplanes and engines, spearheading the production of the groundbreaking 12-cylinder Liberty aviation engine.

Assembly lines increased production in France too. The man sometimes referred to as the “French Henry Ford,” André-Gustave Citroën, left his position at the front as an artillery officer to open an assembly-line based munitions factory in Paris.

Drawing on lessons gleaned from an earlier fact-finding trip to U.S. auto plants, Mr. Citroën’s factory was eventually able to crank out tens of thousands of shells a day at the hands of its mostly female staff. France’s Renault employed assembly lines to accelerate the roll out of trucks and tanks.

The Great War is known by some as the war of production.

These World War I-era production systems laid the groundwork for factory processes in place today—from Germany’s highly efficient car factories to China’s fast-moving consumer technology plants. Now as global centers of manufacturing shift to new emerging markets in Latin America and Asia, the movement of assembly lines continues to wind on, snaking its way onto ever more factory-room floors.

letter d is correct.

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