AP BIOLOGY

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: -Aquatic respiration is the term used when fishes breathe. It is the process of gaseous exchange with water by an aquatic organism, receiving O2 from oxygen dissolved in liquid and removing carbon dioxide and other metabolic products into the water.

Detailed explanation-3: -Fish gills are responsible for a number of critical functions in addition to respiration: osmoregulation, excretion of nitrogenous waste, pH regulation, and hormone production (Herrero et al., 2018).

Detailed explanation-4: -Unlike land animals that have lungs to take in oxygen from air, fish have gills to breathe in the oxygen contained in water. This process of breathing begins when a fish gulps water through its mouth. The water enters the mouth and passes through the feathery filaments in the fish’s gills, which are rich in blood.

Detailed explanation-5: -The gills are structures that allow them to breathe underwater by exchanging gases. For this reason, they have an abundance of blood vessels. Gills are positioned next to the mouth cavity of fish. Fish use their mouths to draw oxygen-rich water in and pump it over their gills.