- Cell theory: cell is smallest unit of life
- Viruses are acellular (do not have cells)
- Lack all cellular machinery
- Cannot replicate outside a host
- Do not ALWAYS have their genetic material in the form of ds DNA
- Do not have all the characteristics of living things
Organization, metabolism, homeostasis, grow/develop/reproduce, adapt, evolve. If you can’t say yes to every single one, you are not a living thing.