Why as viruses described as particles rather than cells?

A single virus particle is known as a virion, and is made up of a set of genes bundled within a protective protein shell called a capsid.

Viruses do not have nuclei, organelles, or cytoplasm like cells do, and so they have no way to monitor or create change in their internal environment. A virus is not a living thing. And they cannot do anything on their own until they enter a living cell. Without cells, viruses wouldn't be able to multiply.

one would be wind another would be water density

compost can be added to topsoil as a:

pesticide