The structure of gills includes thin, highly vascularized membranes with numerous folds and filaments, maximizing the surface area available for gas exchange. Additionally, the countercurrent flow of water and blood within the gills enhances the efficiency of oxygen uptake and ...

The surface area of the gills is crucial for efficient gas exchange in fishes because it allows for a larger area of contact between the water containing dissolved oxygen and the blood vessels within the gills, facilitating the uptake of ...

The primary organ involved in gas exchange in fishes is the gills. Fishes take in water through their mouths and force it past their gills, where dissolved oxygen is absorbed by the blood circulating within the gills.

Aquatic animals have a faster rate of breathing because the amount of dissolved oxygen in water is lower compared to the oxygen content in the air, requiring them to extract oxygen more rapidly from their aquatic environment.

Terrestrial animals breathe oxygen from the atmosphere, while aquatic animals use the oxygen dissolved in water.