1. A formation of protein elements.
2. Life is a 'till it goes up to' kind of existence. You may consider a journey from the beginning to the ending and many combined effects of the probability induced events and outcomes.
3. Life is an existence of a spirit in a biological structure nourished by H2O, Air, and food supplements.
4. Life is, being on this earth (as far as all creatures are limited to this place only) and join the bandwagon of life.
5. Life is a mysterious creation engineered by the almighty. This mystery is still undefined.