Here's why:

* Movement is not essential for life. While many organisms move, there are also many that are sessile, meaning they remain attached to a surface for their entire lifespan. Examples include plants, coral, barnacles, and some bacteria.

* Other characteristics are universal: All living things share characteristics like:

* Organization: They are composed of cells.

* Metabolism: They carry out chemical reactions to obtain and use energy.

* Growth and development: They increase in size and complexity.

* Response to stimuli: They react to changes in their environment.

* Reproduction: They create new individuals.

* Adaptation: They evolve over time to better suit their environment.

Let me know if you'd like to explore any of these other characteristics in more detail!