Final answer:
Kwang-chin Chang referred to the extensive trade network of Neolithic societies in the Yellow River Valley as the “Chinese interaction sphere”, indicating the start of a unified Chinese civilization.
Step-by-step explanation:
Kwang-chin Chang suggested that Neolithic societies in the Yellow River Valley developed a long-distance trade network, which he called the “Chinese interaction sphere”. This concept represents Chang's view that as early as 3000 BC, diverse Neolithic cultures within what is now China were extensively interacting with each other, sharing cultural and technological innovations. The network not only facilitated the exchange of goods but also contributed to the interconnectedness of these societies, leading to the establishment of a unified Chinese civilization that was marked by collective history, motivations, and storylines.