The various characteristics of viruses are:
1. They are smaller and simpler than bacteria.
2. They are ultramicroscopic and visible only under an electron microscope.
3. They are considered to be on the boundary line of living and non-living things.
4. They are obligate parasites and cannot live on their own.
5. They cannot multiply on their own. They require living machinery to multiply.
6. Viruses consist of genetic materials (DNA or RNA) surrounded by a protective coat of protein (capsid).
7. Viruses are responsible for causing many dreadful diseases in plants, animals, and humans.