2. The study of biological processes and materials by means of the theories and tools of physics.
3. The study of physical processes (e.g., electricity, luminescence) occurring in organisms.
4. The science that applies the laws and methods of physics to the study of biological processes.
5. The science dealing with the mechanical and electrical properties of the parts of living organisms.
For example, the principles of electricity have proven instructive in understanding the functions of nervous systems, while the laws of mechanics help to elucidate the workings of the musculoskeletal system.
Various physical techniques have advanced our knowledge of biologically important molecules (that is, proteins and nucleic acids), notably X-ray crystallography, nuclear magnetic resonance imaging, and spectroscopy.