Final answer:
Proof of human-made tools such as flakes is found in the archaeological record, showing the evolution of stone tools from simple Oldowan tools to more sophisticated Acheulean and Mousterian tools, which include hand-axes and specially prepared flakes, indicating advanced cognitive abilities and tool-making skills.
Step-by-step explanation:
The proof of human-made tools such as flakes is evident in the archaeological record, marking advancements in the development and diversification of tool-making over time. The earliest known human-made tools were likely created by Homo habilis and are called Oldowan tools, dating from about 2.6 million years ago. A significant advancement in stone tools came with the Acheulean hand-axes; these improved tools appeared about 1.7 million years ago and were shaped to provide a better cutting, scraping, and chopping functionality. Subsequently, Mousterian tools emerged about 250,000 years ago with Neanderthals and represented a more sophisticated approach where flakes themselves were used as tools rather than solely shaping the core. The evolution of tools continued with the development of the blade tool industry, marked by the shift from round flakes to the manufacture of blade tools during the Upper Paleolithic.
Moreover, Acheulean tools displayed increased cognitive ability and motor skills in the tool maker due to their symmetrical, biface design. The Mousterian tool industry created by Neanderthals provided additional proof of their advanced stone flake tool-making techniques compared to earlier technologies. Finally, the discovery of Acheulean and Mousterian tools in various archaeological sites provides solid evidence of the evolution and sophistication of early human's tool-making abilities.