Biosignature

Any material or molecule or phenomenon – that provides scientific evidence of past or present life is called Biosignature. For example the Biosignature of early life on earth include the microfossils and stromatolites, molecular structures (biomarkers) and isotopic compositions of carbon, nitrogen and hydrogen in organic matter, multiple sulphur and oxygen isotope ratios of minerals; and abundance relationships and isotopic compositions of redox sensitive metals (e.g., Fe, Mo, Cr, and rare earth elements).