The discovery of functional anatomy enabled an integrated view of the cell and, by extension, of the defining features of life. A cell, as noted before, is not just a system of parts sitting next to parts, just as a car is not a carburetor sitting next to an engine. It is an integrating machine that must amalgamate the functions of these individual parts to enable the fundamental features of life. Between 1940 and 1960, scientists began to integrate the separate parts of the cell to understand how an autonomous living unit might function and become “living.”