Final answer:
The people of the Fertile Crescent lost their advantage as the first civilization due to factors including the decline of the Indus Valley civilization and the collapse of the Maya civilization. Other reasons include the complex nature of early empires without a powerful centralized state and the impact of climate change, disease, and warfare.
Step-by-step explanation:
The people of the Fertile Crescent lost their advantage as the first civilization due to a variety of factors. One reason was the decline of the Indus Valley civilization, which was likely caused by regional climate change, environmental degradation, tectonic activity, or epidemic disease. Additionally, the complex nature of early empires without a powerful centralized state contributed to their decline. Another factor was the collapse of the Maya civilization, which may have been influenced by epidemic diseases, invasions, natural disasters, internal revolutions, and environmental degradation. Overall, civilizations can experience decline due to factors such as climate change, disease, and warfare.