Question

Air bladder is present in
A. Dog fish
B. Flying fish
C. Hagfish
D. Electric fish

Answer 1

Fish are classified as aquatic vertebrates and are classified as a living form rather than a taxonomic group. The existence of gills for breathing, fins for mobility, and the incontrovertible fact that they live in water bodies distinguishes them from other species such as amphibians, birds, reptiles, and mammals.
Fishes belong to the Chordate phylum. Gill slits, a notochord, a dorsal hollow nerve cord, and a tail are all distinguishing characteristics. These characteristics set them apart from other animals. The majority of fish are ectothermic, or cold-blooded.

Complete answer:
Option A: Dogfish lack swim bladders and have a cartilaginous skeleton.
So, option A is incorrect.
Option B: Only bony fishes have a swim bladder or air bladder. It's a sac-like protrusion from the oesophagus's dorsal wall. It has a hydrostatic function and, in some situations, it also has respiration. It gives the fishes bouncing and aids in their swimming. Because flying fish are bony fish, they are found in them.
So, option B is correct.
Option C: Hagfish are the only surviving chordates with a partial cranium (skull) but no vertebrae, indicating that they are not true vertebrates. Rather than bone, cartilage makes up the skeleton.
So, option C is not correct.
Option D: The electric eel, despite its name, is a knifefish, not an eel. The backbone of an eel is made up of approximately 100 vertebrae, making it extremely flexible.
So, option D is not correct.

So, option B is the correct answer.

Note:
A swim bladder is a specialised organ that is filled with air and helps the fish maintain a stable buoyancy in the water by regulating its buoyancy. A swim bladder is found in all fish. Air bladders, gas bladders, and fish maw are all names for swim bladders. Fish with air bladders can swim without wasting energy since they can stay at their present water depth. The swim bladder also serves as a sound-producing or-receiving resonating chamber. In fish with a skeletal structure consisting of bones, air bladders are found. Bony fishes are the ones who use swim bladders the most.