Before revision:  Our analysis supports the hypothesis that the mammals' allometric scaling laws of tidal volumes and breathing rates  are driven by a few core geometrical characteristics shared by the mammals' lungs , the physical processes of  respiratory gas transport and the metabolic needs .
After revision:  Our analysis supports the hypothesis that the mammals' allometric scaling laws of tidal volumes and breathing rates are driven by a few core geometrical characteristics shared by the mammals' lungs , the physical processes of respiratory gas transport .