Which type of evidence cannot yield results indicating a common origin or single source?

Single-layer paints cannot yield results that indicate a common origin or single source because they typically lack the complexity and distinct characteristics that multi-layer paints possess. Multi-layer paints are formulated with various layers that each contribute unique properties, such as color, texture, and chemical composition, making it easier to analyze and connect them to a particular source or brand.

In contrast, single-layer paints are more uniform and can be produced in large quantities without significant variation, which complicates the ability to trace them back to a specific origin. This can result in a lack of distinctive features, meaning that while they can certainly be analyzed, it is more challenging to definitively link them to a specific source or match them with samples found at a crime scene.

Composite materials and polyester fibers have their own unique properties and can often lead to conclusive analyses based on their distinctive makeup, further highlighting why single-layer paints do not align with the question's criteria.