Sizes of bulges and bulge galaxies. Effective radii of bulges (R_b, top left panel), disks (R_d, top right panel), and whole galaxies (R_e, bottom left panel) as a function of galaxy stellar mass. Ratios of bulge effective radius to the effective radius of the whole galaxy (R_b/R_e, bottom right panel) as a function of galaxy stellar mass. The median values are indicated by red triangles for classical bulge samples and blue circles for pseudo-bulge samples. The error bars show the 1σ scatter. Dark colour represents results of the selected samples from CANDELS in this work, and light colour represents results of the samples selected at low-redshift from MaNGA by Hu et al. (2024).