Share this credible answer with others. Simply paste this code into your blog or Web page:
The bony fish of the class Osteichthyes are the predominant class of living fishes. In this group the bony skeleton has been retained and lungs and swim bladders have evolved. Early bony fishes evolved in freshwater under conditions of periodic drought and stagnation and developed an internal, moisture-retaining organ, the lung, for gas exchange.
|
Answer verified with
|
HighBeam gives you access to newspaper, magazine, and trade journal articles plus press releases, facts, information, and biographies from thousands of sources.