Answer:
Without any exception, consciousness, cellular organisation, and metabolism are three main characteristics of living beings which differentiate them from non-living things.
Consciousness: It is defined as the state in which living organism is aware of its surrounding and is capable of responding to it.
Cellular organization: Cells are functional and structural unit of the living organism. They collectively form tissues which then form organs. Different organs works collectively to form an organ system which then forms an organism. Organisms collectively form a population
Metabolism: The set of biochemical reaction taking place in a living organism in order to sustain a life is termed as metabolism.