Final answer:
During the Classic Maya period, approximately forty city-states were able to expand. The exact population at its height is uncertain, but it is estimated to have been in the millions.
Step-by-step explanation:
The Classic Maya period, considered to be the golden era, witnessed the expansion of approximately forty city-states. These city-states were ruled by powerful divine lords who exercised their authority through control over religious rituals, construction of temples, and warfare with other city-states. While each city-state remained independent, they shared many cultural attributes. Although the exact population at its height is uncertain, it is estimated to have been in the millions.