Which retail innovation was specifically developed during WWII to efficiently supply U.S. troops but later revolutionized civilian shopping worldwide?

Throughout military history, the logistical challenges of equipping armies has led to groundbreaking retail and product innovations. From standardized uniforms to mass production techniques, military necessity has often driven retail evolution. This trivia question explores one of the most significant wartime retail innovations that transformed both military supply chains and civilian shopping forever.

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Self-service supermarkets with shopping carts
Standardized clothing sizes based on statistical measurements
Mail-order catalogs with military surplus
Canned food with pull-tab openings