What is Life?

Can there be a definition of life? Many potential definitions have been proposed, but none has been accepted as absolute. How can we characterize and define life and living systems, especially in light of the potential for extraterrestrial life to be markedly different from life as we know it?

The ways that life uses specific systems for genetic and catalytic processes, for metabolisms and growth, may be specific to living systems and a way to identify life as we do not know it. These are hypotheses that have to do with what life actually does.