Fig. \[fig1\]. At time $t=0$ the solution contains only two types of supramolecular homopolymer, and as time progresses mixing of monomers occurs at the supramolecular level. However, contrary to crowding of differently labeled monomers at the ends, which is to be expected if monomers can only attach on and detach from the ends, the mixing takes place homogeneously along the polymer backbone. We call their proposed pathway the “*body evaporation and addition*” pathway to contrast it with the conventional *end evaporation and addition* pathway, and study theoretically the kinetics of this pathway in the presence of the *scission and recombination* pathway and *primary nucleation*. [@oosawa] The molecular pathway *scission and recombination* allows polymers to break at any point on the backbone resulting into two smaller polymers and recombining two polymers into a longer polymer. *Primary nucleation* is the mechanism by which a critical number of monomers spontaneously self-assemble to form the shortest stable polymer.[@oosawa] Many researchers have concluded that the time evolution of the length distribution of living polymers is typically a mixture of molecular pathways, which are switched on and off dependent on the system of interest. [@tuomas_science; @hong; @hong_moment_closure] It is for this reason that we study the 