An organisms said to be living, if it shows certain characteristic features that makes it different from non-living thing.
The following properties are defining features of a living
(i) Growth All living organisms show growth either by multiplication or by increase in size. Growth in living things is internal.
(ii) Reproduction All living things produce off springs, possessing features similar to their parents. Thus reproduction is essential to maintain the continuity of life on the earth.
(iii) Metabolism It is the sum total of reactions occurring inside the body by which living things assimilate energy and use it for growth.
(iv) Cellular organisation The cells are the structural and functional unit of living organism.