Final answer:
Modern humans began to form civilizations during the Agrarian Era after the end of the Little Ice Age. The first of these was the Sumer civilization in Mesopotamia, followed by other influential civilizations that emerged along major rivers, such as the Nile, Indus, and Yellow Rivers, marking the beginnings of the Four River Valley Civilizations.
Step-by-step explanation:
Modern humans formed civilizations during the Agrarian Era, which began at the end of the Little Ice Age when Homo sapiens had spread to all inhabitable lands. This era marked the transition from nomadic hunting and gathering to sedentary lifestyles based on farming and raising animals. The first civilization known as Sumer emerged along the Tigris and Euphrates rivers after about 9,000 years of agrarian societies, followed by the Egyptians along the Nile River, the Indus Valley civilization along the Indus River, and the Chinese along the Yellow River, often referred to as the Four River Valley Civilizations.
The development of civilizations is closely tied to the ability of these societies to engage in sustainable farming, water management, social development, the organization of government, and the fostering of progress and innovation. These civilizations, some still in the Stone Age, others transitioning to the Bronze Age, cultivated a broad range of advancements, including the written word and pottery. The ability to produce surpluses of food allowed specialization in various tasks, giving rise to the cradles of civilization.
Early civilizations underwent radical lifestyle changes and significantly altered community interactions, leading to an era filled with contemplative and thoughtful activities such as music, poetry, and philosophy, marking the "dawn of civilization."