a) The main organs of the respiratory system are the lungs. b) There are two lungs in the human body. c) The lungs are separated by the mediastinum. d) The lungs are covered with a double-layered membrane called the pleura. e) Each lung has lobes. f) The vital capacity of the lungs is the maximum amount of air a person can exhale after taking the deepest breath possible. g) The left lung is smaller than the right lung because the heart is located slightly to the left side of the chest, taking up space that the left lung would otherwise occupy. h) The lungs in infants are pink in color. i) Parenchyma is the functional tissue of an organ, in this case, the lung tissue responsible for gas exchange.