Final answer:
A significant demographic development in the two decades following the Second World War was a rapid growth of suburbs.
Step-by-step explanation:
A significant demographic development in the two decades following the Second World War was a rapid growth of suburbs. In the decade between 1950 and 1960, the suburbs grew by 46 percent. The transition from urban to suburban life exerted profound effects on both the economy and society. For example, fifteen of the largest U.S. cities saw their tax bases shrink significantly in the postwar period, and the apportionment of seats in the House of Representatives shifted to the suburbs and away from urban areas.