What characterizes a Mousterian backed knife?

A Mousterian backed knife is characterized by its sharp edge and fine retouch, making it suitable for precise cutting tasks. This type of tool is part of the Mousterian culture, primarily associated with Neanderthals in Europe, and it represents an advancement in tool-making techniques. The fine retouching involves removing small flakes from the tool's edge to create a sharp, finely honed cutting surface.

The other options do not accurately describe the characteristics of a Mousterian backed knife. A thick flake used for skin scraping typically refers to a different type of tool that is not specifically noted for having a sharp edge or fine retouch. A large cobble used for chopping suggests a crude and unrefined tool, which does not fit the more sophisticated design of the Mousterian backed knife. Lastly, a core with multiple flakes removed pertains to the type of tool-making process rather than the specific characteristics of the Mousterian backed knife itself. This process is more related to the production of tools rather than the final tool form that is being described.