What is the definition of a tool mark?

A tool mark is defined as an impression, cut, gouge, or abrasion left on an object that is softer than the object or tool that caused the marks. This definition is fundamental in forensic science because it emphasizes the relationship between the tool and the surface on which the mark is made. The tool must be harder than the material to create an impression or damage, which helps in analyzing and linking tools to potential crime scenes.

In forensic investigations, tool marks can provide critical evidence regarding a tool's possible use in committing a crime. The characteristics of the mark can reveal details about the tool's size, shape, and design, which can be crucial for matching a specific tool to a crime scene.

The other options do not accurately capture the comprehensive nature of what a tool mark entails. For instance, the first choice mistakenly specifies that the impression must be left on a surface harder than the tool, which contradicts the principle of how tool marks are formed. The definition in the third option restricts tool marks to marks made only on metal objects, overlooking the variety of materials that can be involved. Finally, the fourth choice generalizes the origin of the scratches without mentioning the comparative hardness necessary for defining a tool mark. Thus, the second option accurately encapsulates