Fish gills have great efficiency, especially due to the use of countercurrent flow, while amphibians, with positive pressure breathing, are much less efficient. Mammals have lots of lung surface area, but tidal breathing is an inefficiency. Birds have unidirectional flow as well as lots of surface area, making their lungs very efficient.
Work Step by Step
This question basically asks you to review and summarize, by comparison, the working of four kinds of gas exchange featured prominently in this chapter.