Ans. 'Presence of genetic material.'
The viruses are known as connecting link between living and non-living things as they show characteristics of both. All viruses have their own genetic material, either as DNA or RNA.
Three domains of life include bacteria, archea, and eukarya. All organisms of these three domains also have their genetic material in the form of DNA.
Thus, the characteristic that applies to viruses and all three domains is presence of genetic material.