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A virus has either a DNA or an RNA genome and is called a DNA virus or an RNA virus, respectively. The vast majority of viruses have RNA genomes. Plant viruses tend to have single-stranded RNA genomes and bacteriophages tend to have double-stranded DNA genomes.
Viroids are a small RNA that infect plants. They are 80 times smaller than a typical virus and consisting only of a nucleic acid without a protein coat. In order to protect themselves since they do not have a protein coat they mask themselves appear to be items from the host organism's cell.here are many forms of viruses and they can do remarkably terrible things. The most common form of a virus is the Influenza virus, or even more commonly known; the flu. It can be spread as all viruses through the air, by being swallowed, or inhaled, and also through skin to skin touch.