Final answer:
Modern historians support overpopulation, environmental degradation, and warfare theories as reasonable explanations for the decline of Mayan civilization.
Step-by-step explanation:
Modern historians support the theories of overpopulation, environmental degradation, and warfare as reasonable explanations for the decline of Mayan civilization.
Firstly, the Mayan civilization experienced rapid population growth, which strained their resources and led to social unrest.
Secondly, extensive deforestation and soil erosion caused environmental degradation, further exacerbating the society's challenges.
Lastly, continuous intercity warfare and conflicts over resources contributed to the decline of the civilization.
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