ABSTRACT
The constrained disorder principle (CDP) defines living organisms as systems that comprise an intrinsic disorder bounded by dynamic boundaries. Water plays a substantial role in multiple biological processes affecting nucleic acids' and proteins' structure and function. The paper describes the CDP-accounted water structure dynamicity and variability in water isomers ratio. Per the CDP, the variability in the ratios between water isomers is mandated for the inherent variability of biological systems. This variability underlies water's unique functions and enables the flexibility and adaptability required to cope with internal and external environmental changes. The CDP-dependent water structures also determine energy usage. The paper presents water molecules as ultimate biosensors for stimuli in the environment and as the ultimate bioreactors that respond to perturbations by changing the structure and function of the molecules in their vicinity. Finally, it describes the potential of using water-based signatures of variability to improve artificial intelligence-based algorithms developed for correcting disturbances of biological systems by increasing the degree of disorder in systems or tightening the disorder's boundaries.