I want to know the answer to the following question:
What has demonstrated a history of sign use in the Yellow River valley?
All the background I'm provided with is that "However, because these marks occur singly, without any implied context, and are made crudely and simply, Qiu Xigui concluded that "we do not have any basis for stating that these constituted writing nor is there reason to conclude that they were ancestral to Shang dynasty Chinese characters.". Is that enough to answer the question?