DENDROLOGY

Detailed explanation-1: -Fish take water into their mouth, passing the gills just behind its head on each side. Dissolved oxygen is absorbed from-and carbon dioxide released to-the water, which is then dispelled. The gills are fairly large, with thousands of small blood vessels, which maximizes the amount of oxygen extracted.

Detailed explanation-2: -Fish use their gills to help them breathe. The majority of fish have gills on both sides of their heads. Gills are tissues made up of gill filaments, which are feathery structures that provide a wide surface area for gas exchange.

Detailed explanation-3: -Although most fish respire primarily using gills, some fish can at least partially respire using mechanisms that do not require gills.