It is because viruses are not made up of cells
Rna and dna
They are classified by a number of different viral characteristics. These include DNA vs. RNA viruses, single strand (SS) vs. double strand viruses (DS), enveloped vs. non enveloped, or retrovirus. For example the HIV virus is an enveloped single stranded RNA retrovirus.
Viruses are not living things. Viruses are complicated assemblies of molecules, including proteins, nucleic acids, lipids, and carbohydrates, but on their own they can do nothing until they enter a living cell. Without cells, viruses would not be able to multiply. Therefore, viruses are not living things.
Color shape size textures
lichens, corals, viruses, corals, viruses and carnivourous plants are difficult to classify :)
It is because viruses are not made up of cells
Viruses can be labeled as RNA or DNA viruses and they can be said to have an envelope or to be "naked".
their genome
size and shape
Rna and dna
Viruses need living cells to produce more viruses. They are obliged to use living cells.
reptiles are animals so all of their features classify. reptiles are not mammals though if that what is being asked.
Living. Because viruses are caused by germs...which are living organisms
Viruses lack the characteristics of living organisms, such as cellular structure and metabolism, making it challenging to classify them within the traditional system of biological classification. Additionally, viruses are considered obligate intracellular parasites that can only replicate inside host cells, further complicating their classification within the existing kingdom system.
They have a spine.
Animals and money