  Reaction systems, introduced by Ehrenfeucht and Rozenberg, are elementary
computational models based on biochemical reactions transpiring within the
living cells. Numerous studies focus on mathematical aspects of minimal
reaction systems due to their simplicity and rich generative power. In 2014
Manzoni, Pocas, and Porreca showed that every reaction system can be simulated
by some minimal reaction system over an extended background set. Motivated by
their work, we introduce the concepts of strictly minimal and hybrid reaction
systems. Using our new concepts, the result of Manzoni et al. is revisited and
strengthened. We also show that extension of the background set by polynomially
bounded many elements is not sufficient to guarantee the aforementioned
simulation. Finally, an analogous result for strong simulation is obtained.
