How is the modern era different from the post classical era ?

A. In the postclassical era, the world's most powerful states were in in Asia and the Middle East. In the modern era, power shifted to Eurasia.

Explanation:

During the Post-Classical era (600 CE to 1450 CE), areas previously under control of the Empires underwent an economic decline.  The fall of Rome brought new possibilities in the Middle East, and Arabs regain control over areas under Roman rule.

During the Early Modern (1450-1750) and the Modern era (1750-1900), Eurasia had the most powerful states, changing the power distribution.