Is This List of Life Really a List of Life?

Each and every one of the cells in our body is constantly using energy to continue whatever its process is. But that is something that even a single celled organism can do, but can a virus? So are we going to be able to apply this list to extraterrestrial species if they aren't exactly like this? I think it gets to the latter. Scientists over multiple years have been defining what we already think it's alive. And this is why it's so difficult to then look at things that don't fit in this list to ask or define whether or not they live.