What type of evidence is 'DNA' considered in forensic investigations?

DNA is considered biological evidence in forensic investigations because it is derived from living organisms. It is a complex molecule that contains the genetic instructions for the development, functioning, growth, and reproduction of organisms. In a forensic context, DNA obtained from blood, hair, skin cells, or other bodily fluids can be crucial in identifying individuals involved in a case.

This type of evidence is particularly valuable because it is unique to each individual (except in the case of identical twins), which allows forensic scientists to match DNA samples from a crime scene to potential suspects or victims. The specificity and reliability of DNA as biological evidence contribute significantly to its use in solving crimes and establishing connections between individuals and crime scenes.

Other types of evidence mentioned, such as circumstantial, documentary, and physical, serve different purposes in investigations. Circumstantial evidence relies on inference rather than direct proof. Documentary evidence pertains to written or recorded materials that can provide information relevant to a case, while physical evidence encompasses tangible items that can be seen or touched, but would not specifically involve the biological component inherent in DNA.