Apog:
Plants move. = Tropism
The startle reflex is mediated by the nervous system. Rocks don't have nervous systems. You don't startle rocks. The whole purpose behind the startle reflex is to avoid coming in contact with something dangerous.
The many arrangements we each have with our personal parasites doesn't alter the identity of the organism as a whole. You can kill the yeast infection and the organism continues. If you extract the gold from the quartz you don't have the same rock anymore.
The problem with your summary of nervous system activity is that rocks simply don't have nervous systems. It doesn't explain anything.
That's the whole point. It's not a difference in degree but a difference in kind.
You might say that rocks have a relationship with everything in the universe, but those relationships don't "mean" anything to the rock. Rock A might be 3 cm from rock B. Who cares? Yes - WHO cares and a WHO is an organism in contrast to a rock that is merely a WHAT.
Meaning, also called value, requires a living organism.