Q.List three features that characterise bony fishes.

Step 1. The class name Osteichthyes itself points to the first defining feature: a fully bony endoskeleton, in contrast to the cartilaginous skeleton of Chondrichthyes.

Step 2. A second feature is the operculum, a bony flap covering and protecting the four pairs of filamentous gills on each side — a structure entirely absent in cartilaginous fishes. …

Pick three features explicitly named in the Osteichthyes description that di …

• Listing features shared with cartilaginous fishes (such as fins or gills generally) instead of the ones specific to bony fishes. …