He did touch on relation, maybe he'll go into more detail later on. Regarding a cell, I don't know, I'm hardly qualified to give an opinion, but while there are one-celled organisms, even so they have parts to them...cytoplasm, ribosomes, etc. so there's an intra-cellular dependency. And any other type of multicellular organism couldn't exist without dependency on other cells and the interactions between them. For example, during a neuronal action potential, sodium channels are opening and closing during polarization and depolarization. In this process, sodium and potassium are moving in and out of the cell. This interdependency in just one small but absolutely essential process makes me wonder if it's impossible for a cell to be without relation.