Left panel: observed MZRs adopted at different redshifts: the local MZR by Kewley & Ellison (2008) is depicted with the blue line, and the high-redshift MZR by Maiolino et al. (2008) with the red line. The dashed red line is the MZR observed by Mignoli et al. (2019) at z ∼ 2. With the solid green line we also show the local MZR relation for SDSS galaxies found by Curti et al. (2020) with a fully T_e-based abundance scale analysis. Middle panel: star-forming main sequence by Peng et al. (2010) in local SDSS galaxies shown with the blue line, and the high-redshift relation is from Pearson et al. (2018). Right panel: with the dashed black line we show the SFE as a function of the infall mass M_inf from the scaling relation for the gas-depletion timescale as found by Boselli et al. (2014). The constant SFE fixed at the value of 1 Gyr⁻¹ is indicated with the light blue curve.