Bony fishes have sac-like outgrowth, called air bladder arising from d...
As air bladder provide buoyancy thats means fish will not have to swim continuously to avoid sinking so option(a) is incorrect, as fins helps in changing directions and not the air bladder so option (b) is also incorrect. So answer goes to (c) as it helps in up and down motion. Chondrichthyes need to swim constantly to avoid sinking as the don't have air bladder.
Bony fishes have sac-like outgrowth, called air bladder arising from d...
**Explanation:**
The correct answer is option 'C' - "Maintain balance and to swim up and down, Maintain buoyancy for swimming."
The air bladder, also known as the swim bladder, is a sac-like outgrowth found in bony fishes. It is located in the dorsal wall of the oesophagus, which is the tube-like structure connecting the mouth and stomach in the fish.
**Function of the Air Bladder:**
The air bladder serves several important functions in bony fishes:
1. **Maintain Buoyancy for Swimming:** The primary function of the air bladder is to provide buoyancy to the fish, allowing it to maintain a specific depth in the water without sinking or floating to the surface. The air bladder acts as a hydrostatic organ, counteracting the weight of the fish's body and providing neutral buoyancy. By adjusting the volume of gas within the air bladder, the fish can control its buoyancy and stay at the desired depth in the water column.
2. **Maintain Balance and Swim Up/Down:** The air bladder also helps in maintaining balance and allows the fish to swim up and down in the water column. By controlling the volume of gas in the air bladder, the fish can adjust its overall density and change its vertical position in the water. If the fish wants to swim upwards, it increases the gas volume in the air bladder, reducing its overall density and allowing it to rise. Conversely, if the fish wants to descend, it decreases the gas volume, increasing its density and enabling it to sink.
3. **Changing Direction for Swimming:** While the air bladder primarily helps with maintaining buoyancy and balance, it indirectly aids in changing direction for swimming. By altering its vertical position in the water column, the fish can adjust its orientation and change direction as needed.
In conclusion, the air bladder in bony fishes serves multiple functions, including maintaining buoyancy for swimming, maintaining balance and enabling the fish to swim up and down in the water column. Therefore, option 'C' - "Maintain balance and to swim up and down, Maintain buoyancy for swimming" is the correct answer.
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