Cumulative distribution of the molecular mass (left vertical axis and solid lines) of the 90 pc regions in the dual galaxies, selected applying a cut on Σ_H2, as a function of the radial distance. The dashed lines (right vertical axis) show the cumulative distribution of the number of regions in each branch. Colours are as in Fig. 1. The dash-dotted lines correspond to the radii that include a percentage of regions.