Which of the following is a class characteristic of evidence?

A class characteristic of evidence is a feature that can be associated with a group but not a single source. Threads of a specific fabric type are classified as class characteristics because they can help link evidence to a particular category or type of material, such as the brand of clothing or fabric type, which may be shared among many items but does not uniquely identify one specific piece of evidence.

In contrast, unique scratches on a shoe sole or individual markings on a bullet are examples of individual characteristics, which can pinpoint a specific source. Blood type found at a scene also represents a class characteristic, but it is typically broader than fabric type, encompassing groups like A, B, AB, and O blood types, rather than specifying a type of fabric, which is more detailed. Therefore, the correct answer captures the essence of class characteristics effectively.