<prompt> Locards principle is concerned:Theory of relativityTheory of decompositionTheory of traumaTheory of exchagnge  <response>: Ref. Textbook of forensic medicine. Krishnan Vij. Page. 302 Locard Principle:When any two objects come into contact, there is always a transfer of material from each object on the other.Some examples are fingerprints, footprints,hair, tool marks etc. 