* Organization: Living things are composed of cells, which are the basic unit of life. Viruses, on the other hand, are not made of cells.
* Metabolism: Living things take in energy from their environment and use it to grow, reproduce, and maintain their structure. Viruses do not have a metabolism and cannot grow or reproduce on their own.
* Response to stimuli: Living things respond to their environment by changing their behavior or physiology. Viruses do not respond to stimuli.
* Reproduction: Living things reproduce by creating offspring that are similar to themselves. Viruses reproduce by infecting other living cells and using their machinery to make copies of themselves.
* Growth and development: Living things grow and develop over time. Viruses do not grow or develop.
* Adaptation: Living things adapt to their environment over time, which allows them to survive and reproduce. Viruses do not adapt to their environment.
Because viruses do not meet the criteria for life, they are not considered to be "things."
