english: The lung is thought to have evolved as a structure to allow early fish, many of which lived in warm, stagnant water with little oxygen, to take advantage of the abundant oxygen in the air overhead.
non_english: Pljuča naj bi se razvila, da bi prvim ribam, ki so pogosto živele v toplih stoječih vodah z malo kisika, omogočila izkoriščanje s kisikom bogatega zraka nad gladino.