1. a) 889 CE
2. b) Because of warfare and failing agriculture
3. b) Because of sinkholes providing fresh groundwater
4. c) It shifted to include ruling councils of the city’s elite
5. b) Obsidian, gold, copper, turquoise, and jade
6. c) By keeping track of time, celestial bodies' transit and agricultural cycles
7. c) K’uk’ulkan, the feathered serpent god
8. d) A century-long drought
9. c) The population decreased and many people moved to the coast
10. c) Mayapan