Final answer:
Cortés ended the Aztec Empire by utilizing superior Spanish military tactics and weaponry and by allying with indigenous tribes opposed to Aztec rule. The correct option is 1.
Step-by-step explanation:
Two important reasons why Cortés was able to put an end to the Aztec Empire were superior military tactics and weaponry, and support from other indigenous tribes. The Spanish conquest, led by Hernán Cortés, capitalized on these advantages. The Spanish brought formidable military technology such as steel swords and armor, firearms, and cavalry, which were unknown to the Aztec forces.
Additionally, Cortés skillfully forged alliances with indigenous groups like the Tlaxcalans who resented Aztec dominance and saw the Spanish as a means to overthrow their oppressors. These alliances were crucial in bolstering the Spanish forces with tens of thousands of indigenous fighters.
Hence, Option 1 is correct.