Based on this week's readings, it appears that any item can be reduced to its smallest parts and be defined as trace evidence. However, what is the underlying reason why paint scrapings from hit and run accidents, soil collected from death investigations, hairs collected in a sexual assault kit, and fibers collected from a residential burglary would be considered trace evidence warranting collection? What does each of these examples demonstrate that separates them as trace evidence from anything else found at a crime scene?