Average trends of the concentration index as a function of sSFR. Each row shows the scatter plot of the sSFR–C relation for the stellar continuum emission and three different spectral lines. Left column: the data are binned according to the morphological group they are belong to, similarly to Fig. 10. Middle column: galaxies are binned according to their stellar mass into low M_star (log M_star < 10.4), moderate M_star (10.4 ≤ log M_star < 10.82), and high M_star (log M_star ≥ 10.82). Right column: galaxies are binned according to their star-formation activity into low SFR (log SFR < −0.52), moderate SFR (−0.52 ≤ log SFR < 0.14), and high SFR (log SFR ≥ 0.14). All bins were defined in such a way so that they contain roughly one third of the objects in our sample. The error bars are the standard deviation of the mean values.