The linked article discusses the lung fish which has gills for getting oxygen from water and a lung that can be used to extract oxygen from the air. It seems th

The linked article discusses the lung fish which has gills for getting oxygen from water and a lung that can be used to extract oxygen from the air. It seems that this is an example of different structures used for the same purpose, extracting oxygen from the environment, but not the same task. One task extracts oxygen from water and the other from air.