Biology focuses on processes and relationships of living organisms. Life operates according to laws of the physical world, as well as genetic programming. Biologists use observations, experiments, hypotheses, tests, models, theory, and technology to explore how life works. The study of life ranges over scales from single molecules, through organisms and ecosystems, to the entire biosphere. It also examines processes that occur on a variety of time scales. Living systems are interconnected and interacting while responding to the physical environment. Rapid advances in biology are helping to provide solutions to societal problems.