Viruses are not living organisms
Viruses are not considered living organisms. They cannot live independently, but instead always require a host species in order to survive. Viruses are small parasites that live in the cells of living organisms. They are so small that one cell can contain thousands of them.
Many viruses are harmful. They cause illnesses, such as the flu.
Viruses spread easily from one living organism to another. This is why it is important to take care of your hygiene.
Photograph on the right: A microscopic image of a virus. The genome of the virus is located under its shell.