Another qualification of life is its genetic make-up. All organisms must have some sort of DNA as its basis for its characteristics. Some organisms have more genes than others, but all have some. These genes are passed on, through the reproductive process, to the offspring of the parent or parents. RNA could be seen as the genetic base for early life.
All life relies on the intake of certain compounds to sustain itself.
All organisms need foreign substances to sustain themselves. All organisms have a life-span. Some trees have been known to live up to 6000 years while fruit fly generations often last less than a week. All life, as we know it, is based on organic molecules composed of carbon atoms. This alone does not define life, but with other characteristics it excludes fake life-forms such as computer viruses.