Definition relative dating
Death is the permanent termination of all biological functions which sustain an organism, and as such, is the end of its life.Extinction is the process by which an entire group or taxon, normally a species, dies out.
Abiogenesis describes the natural process of life arising from non-living matter, such as simple organic compounds.The criteria can at times be ambiguous and may or may not define viruses, viroids, or potential artificial life as "living".Biology is the primary science concerned with the study of life, although many other sciences are involved. The current definition is that organisms maintain homeostasis, are composed of cells, undergo metabolism, can grow, adapt to their environment, respond to stimuli, and reproduce.Earth's current life may have descended from an RNA world, although RNA-based life may not have been the first.The mechanism by which life began on Earth is unknown, though many hypotheses have been formulated and are often based on the Miller–Urey experiment.
Life is a characteristic that distinguishes physical entities that do have biological processes, such as signaling and self-sustaining processes, from those that do not, either because such functions have ceased, or because they never had such functions and are classified as inanimate.