Answer:
The correct answers are A) The Spanish took Moctezuma prisoner. C) Smallpox weakened the Aztecs' ability to resist. D) The Aztecs welcomed the Spanish with gifts.
The statements that describe an event that contributed to the decline of the Aztec Empire were the following: The Spanish took Moctezuma, prisoner, smallpox weakened the Aztecs' ability to resist. and the Aztecs welcomed the Spanish with gifts. The big problem for the Aztecs was that they confused the Spaniards with the gods of its prophecy. The Aztecs were waiting for Quetzalcoatl God, and they thought it was Herna Cortéz. So the Aztecs completely welcomed the Spaniards and offered them gifts as if they were gods. That is why it was so easy for the Spaniards to take Emperor Moctezuma as a prisoner. New diseases unknown to the Aztecs such as smallpox, chickenpox, influenza, and malaria, also contributed to its loss to the Spanish.