The lung.
D006801:Humans; D008168:Lung / Q000033:anatomy & histology / Q000098:blood supply / Q000502:physiology / Q000503:physiopathology; D008171:Lung Diseases / Q000209:etiology / Q000503:physiopathology; D008175:Lung Neoplasms / Q000209:etiology; D016040:Lung Transplantation; D011650:Pulmonary Alveoli / Q000166:cytology; D011655:Pulmonary Embolism / Q000209:etiology; D011656:Pulmonary Emphysema / Q000503:physiopathology; D012137:Respiratory System / Q000294:innervation; D012907:Smoking