The robustness of biological processes is remarkable given that the underlying cellular chemical reactions are inherently stochastic. Thus, cells and organisms must compensate for this natural variability. One compensation method is redundancy. For example, organisms often make more cells than are needed and killing off the excess or have redundant promoters, binding elements, and transcription factors to ensure gene expression. Redundancy ensures that biological events occur (and occur at the correct time), but redundant systems have an inherent problem: they are difficult to change. In fact, their very nature is to resist change. We have discovered an alternative means of ensuring in the development of the nervous system of the nematode Caenorhabditis elegans that does not involve redundancy, and so has a potential for modulation.