Describe two characteristics of classical civilizations. then, explain how those characteristics differentiate classical civilizations from early river valley civilizations.

Characteristics are:
1) Complex governments - political organizations were more developed in classical civilizations. For example Greece (in Athens free men made political decisions, democracy for adult males), in Rome there was Republic (ruled by aristocrats).
2) Trade and economic systems were more developed in classical civilizations. 
Trade routes were connected by land and sea, for example Han era in China (trade along the Silk Road)

the following best describes postwar era writers in their works:

progressive

many writers,authors,novelists,poets concentrated more on social art and social writing and stayed away from political writings.