Practice problem
Multicellular Life — Definition & Overview
By Valeri Natole
+2 contributors
Contributors
By AndreasHeinemann GFDL or CC-BY-SA-3.0, via Wikimedia Commons
In many organs, such as the lungs, there is folding. (You can see this in the lungs pictured above!) Without this folded layout, the surface area of the lungs is the size of half a tennis court! What functional purpose do folded structures serve?