Gills

Gills are a type of respiratory organ found in aquatic animals including fish, crustaceans and molluscs. Gills allow these animals to absorb dissolved oxygen from water and, as a result, they are essential for survival in their aquatic environment. Gills are composed of thin sheets of tissue containing many blood vessels which allow oxygen to be extracted from the water. Additionally, gills also act as filters to remove debris, waste materials and other harmful substances from the water. Gills are highly specialized organs and are a key factor in the success of aquatic animals. They are also seen as a key indicator of water quality, as poor water quality can impact the efficiency of gills, ultimately affecting the health of the organism.