Viruses are considered to be living organisms because they

Viruses are not considered to be living organisms because they do not possess all the characteristics that define life. While they do possess transmittable characters, they do not have the ability to move, respond to stimulation, or ingest food materials. Additionally, viruses cannot reproduce on their own and instead require a host cell to replicate. Because of these limitations, viruses are often classified as "non-living" or "acellular" entities that exist in a gray area between living and non-living.