A reaction network, in the context of chemistry and chemical engineering, is a visual or mathematical representation of the interconnected chemical reactions that occur within a system. It is a way to depict how different chemical species (reactants and products) interact and transform into one another over time. Reaction networks are essential tools for understanding complex chemical processes, such as those in biological systems, industrial chemical reactions, and environmental reactions. Biochemical reaction networks are representations of interconnected chemical reactions that occur within biological systems, encompassing the complex web of molecular interactions in living organisms. Each node or component in the network represents a specific chemical species, which can be an element, a compound, or a molecule involved in the reactions. The edges or links between nodes represent chemical reactions. These reactions describe the conversion of one or more reactants into one or more products, typically following a stoichiometric relationship. Reaction networks often include information about the stoichiometry of each reaction, specifying the molar ratios of reactants and products involved. Some reaction networks indicate the directionality of reactions, distinguishing between forward and reverse reactions.