Which best explains the Mesopotamian practice of placing ziggurats at the center of their city-states.

The Mesopotamian practice of placing ziggurats at the center of their city-states can best be explained as a reflection of the cultural, religious, and political importance these structures held in their society. Ziggurats were massive terraced pyramid-like structures that served as the base for temples. They were thought to bridge the gap between the earth and the heavens, acting as a dwelling place for the gods. The central placement of ziggurats within city-states symbolized the central role of religion and the gods in Mesopotamian life. Moreover, having the ziggurat at the heart of the city also highlighted the political power of the priestly class, as the priests were responsible for ritual activities and held significant influence over the city's governance. This central positioning could thus reinforce the authority and control of the ruling class over the inhabitants of the city-state.

Mesopotamia, often referred to as the "cradle of civilization," was located in the region of the Tigris-Euphrates river system, which is present-day Iraq and parts of Iran, Syria, and Turkey. The region is known for the development of some of the earliest urban societies around 3100 BCE. City-states such as Ur, Uruk, and Babylon were among the most prominent in the region, each with its own ziggurat.