Who caused the Decline of the Mayan Civilization?

Which statement describes a similarity between the great migration and to this day

How was slavery in mesoamerica, africa, and the arab world similar? many enslaved people were forced to pledge loyalty to their owners. many enslaved people worked in exchange for protection from foreigners. many enslaved people were captured during war. many enslaved people taught and tutored children.

How did tyrants attempt to gain the approval of common citizens in ancient greece?