evolution is complex, the scaling relations between metallicity and other galactic properties provides a powerful alternative approach.

Since its establishment by [@Lequeux1979a], the relation between stellar mass and metallicity has been studied for decades [e.g. @Garnett1987a; @Tremonti2004]. It is a positive correlation, meaning that the metallicities of galaxies increase with increasing stellar masses. The significant scatter in the stellar mass – metallicity relation (MZR) implies the complication of the underlying physical and chemical processes in an evolving galaxy. Variations in galactic parameters, such as the star formation rate (SFR), the 4000 $\mathrm{\AA}$ break ($D_{\rm n} 4000$), and the galaxy size and morphology, are found to contribute to the scatter in MZR [e.g. @Ellison2008; @Mannucci2010a; @Yates2012; @Andrews2013; @Lian2015; @Bothwell2016; @Wang2018]. In particular, using the SDSS Data Release (DR) 7 [@Abazajian2009], [@Mannucci2010a] and [@Andrews2013] found that metallicity to be anti-correlated with SFR at a fixed stellar mass, and the scatter in MZR is siginificantly suppressed when a stellar mass – SFR – metallicity relation (fundamental metallicity relation; FMR) is constructed. Nevertheless, with the same data SDSS DR7, [@Salim2014] argued that a more physically motivated second parameter for the MZR is the specific SFR (sSFR) when ${\rm log}(M_*/M_\odot) \leq 10.5$. [@Bothwell2016] derived the 