title: Skin breathing--primary or secondary?
mesh_terms: D000222:Adaptation, Physiological; D000663:Amphibians / Q000502:physiology; D000818:Animals; D005075:Biological Evolution; D005399:Fishes / Q000502:physiology; D005880:Gills / Q000502:physiology; D008168:Lung / Q000502:physiology; D012119:Respiration; D012879:Skin Physiological Phenomena