Which statement best describes the political structure of the ancient aztecs?
a. the aztecs developed city-states that were powerful but independent.
b. the aztec civilization included different groups unified under a single religion. c. the aztec civilization was ruled by an emperor and had about four hundred tribute states.
d. the aztecs were ruled by representatives from different city-states.

C.The Aztec civilization was ruled by an emperor and had about four hundred tribute states.

Explanation:

The aztecs were a warriors civilization they conquered the vast majority of the mesoamerican tribes and were all under their control, they took ributes from them and had the greatest capitol city in the americas, were very organized and had a centralized control government, this was the emperor who decided and guided the empire.

nothing certain is known about what happened, but it seems that the country declined gradually, perhaps due to bad government, or, more likely, due to a series of bad harvests, which resulted in widespread and recurrent famine.