(u − r) colour vs. stellar mass diagram (CMD) for our random sample independent of the environment. The CMD density isocontours are shown in gray. Points with error bars represent the mean and standard deviation of Gaussian fits for the blue cloud (BC, blue symbols) and the red sequence (RS, red symbols) as a function of stellar mass. The shaded region represents the GV, which comprises 13.15% of the sample of galaxies, while the hatched area designates the GZ, which contains 3.75% of the sample.