Why each civilization from Greece was “classical”?

The civilization of ancient Greece was immensely influential in many spheres: language, politics, educational systems, philosophy, science, and the arts. It had major effects on the Roman Empire which ultimately ruled it. As Horace put it, "Captive Greece took captive her fierce conqueror and instilled her arts in rustic Latium."

Via the Roman Empire, Greek culture came to be foundational to Western culture in general. The Byzantine Empire inherited Classical Greek culture directly, without Latin intermediation, and the preservation of classical Greek learning in medieval Byzantine tradition exerted strong influence on the Slavs and later on the Islamic Golden Age and the Western European Renaissance. A modern revival of Classical Greek learning took place in the Neoclassicism movement in eighteenth- and nineteenth-century Europe and the Americas.

Explanation:

sumerians were responsible.

according to worldatlas.com, the u.s. has an 86% literacy rate.