The body is always trying to maintain homeostasis by either allowing or removing certain particles/molecules/chemicals/compounds/..
What Bodies Think About: Bioelectric Computation Outside the Nervous System - NeurIPS 2018 - Incredible research. (HN)
Kappa - Rule-based language for modeling systems of interacting agents. While its current development is primarily motivated by molecular systems biology, its range of applications is quite broad.
KaSim - Stochastic simulator for rule-based models written in Kappa. KaSa is a static analyser for Kappa models.
BioJulia - Julialang community for biologists and bioinformaticians, working to create great modern software packages for computing with biological data.