Final answer:
A northern nomadic people migrated into the Yellow River valley between 2000 BCE-1600 BCE, a region critical for the development of farming and settlement in early dynastic China due to its fertile loess soil, despite frequent flooding.
Step-by-step explanation:
Between 2000 BCE-1600 BCE, a northern nomadic people migrated south into the Yellow River valley. This period marks significant migrations as these nomadic groups moved into established river valleys, playing a key role in the development of Chinese civilization. The Yellow River, known for its loess soil, was critical for farming and human settlement due to its fertility, but also prone to heavy flooding, differing from the controlled irrigation seen in ancient Egypt. Alongside the Yellow River, the Yangtze River valley also saw the growth of Neolithic settlements, particularly in the cultivation of rice agriculture.