What was an important advantage that hernán cortés had during his attacks on the aztec?

Fire arms and cavarly.

Explanation:

Hernán Cortés´s invading battalion had many advantages over the Aztec people like the fact that European contagious diseases like smallpox early on considerable decimated the Aztec population and also the fact that Cortés was able to form alliances with other tribes that were eager to overthrow the Aztec empire. However, when it came to the battle itself, it was the fact that the Spanish had fire arms and cavalry, that is, in basic terms, horses, what made the Spanish able to take over the Aztecs.    

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you didn't list the options. however, a few communist countries today are: the people's republic of china, north korea, and cuba.