Final answer:
The decline of the Mayan civilization is attributed to environmental degradation, climate change leading to drought, and relentless warfare, with evidence suggesting a confluence of these factors.
Step-by-step explanation:
There are three main theories about what happened to the Mayan people. One theory suggests that environmental degradation, such as deforestation and soil exhaustion, led to agricultural decline and malnutrition, precipitating societal collapse. Another theory points to prolonged drought and climate change as critical factors that strained the Mayan civilization's water supply and diminished their ability to sustain large populations. The third popular theory argues that incessant warfare among competing city-states, along with internal sociopolitical turmoil, eroded the fabric of Mayan society. These theories highlight the complexity and multi-causal nature of the Classic Maya decline, with recent evidence suggesting that a combination of these factors, rather than a single cause, likely contributed to the eventual fragmentation and transformation of Mayan society.