whether and to what extent the emergent properties can be explained in terms of the elements of the lower level.

There is, then, no unique place to look for the answer to how life works. Life is a hierarchical process, and each level has its own rules and principles: there are those that apply to genes, and to proteins, to cells and tissues and body modules such as the immune system and the nervous system. All are essential; none can claim primacy. As Nobel l

As we discuss in Section 4.3, the essential properties of a living system are emergent properties – properties that are not found in any of the parts but emerge at the level of the system as a whole.