Explanation:

Viruses are too small to be seen by the naked eye. They can't multiply on their own, so they have to invade a 'host' cell and take over its machinery in order to be able to make more virus particles.Virus infects all of the given organisms (Bacteria, Fungi and Plant). Viruses are known to infect almost any kind of host that has living cells. Animals, plants, fungi, and bacteria are all subject to viral infection.

A bacteriophage is a virus that infects and replicates within a bacterium. Mycoviruses are viruses that infect fungi. A host of other Viruses affect plants.