Occasionally an individual who remains at high altitude for too long develops chronic mountain sickness. It is characterized by the following clinical sequelae: (1) an exceptionally high hematocrit; (2) elevated pulmonary arterial pressure; and (3) an enlarged right side of the heart. As it progresses, congestive heart failure and death ensues unless the person is removed to a lower altitude. Describe how the body normally adapts to elevated altitude and the causes for the sequence of events associated with chronic mountain sickness.