Which of these developments occurred during the 1950s and 1960s as the american middle class achieved greater levels of prosperity

The answer is that suburban spread quickly. In the 1950s, the American Dream became an actual thing. It was within their reach was the chance to have a house on their own land, a car, a dog, and kids. Between 1950 and 1956 suburbs go up by 46% and thousands of acres of farm and forest were tuned into suburbs.

classical republicanism, also known as civic humanism, is a form of republicanism  developed in the renaissance inspired by the governmental forms and writings of  classical  antiquity, especially such  classical  writers as aristotle, polybius, and cicero.