2 Usage Examples Depicting the Meaning of 'Virus' in a Sentence

"A tiny infectious agent, too small to be seen with a regular microscope (20 to 300 nanometers in diameter). Viruses are not alive on their own and can only replicate inside the cells of living hosts, such as bacteria, plants, and animals. They consist of a core of RNA or DNA, a protein coat, and, in more complex types, a surrounding envelope." more