What do animals breathe with?

Animals carry out gas exchange with the help of various organs. Some representatives of the animal world breathe using the surface of the skin. For example – earthworms. That is why worms crawl to the surface of the soil after rain, as the water floods them and they cannot breathe. More complex organisms have lungs. These are the majority of large animals. Birds also have air sacs other than their lungs. In the lungs, the blood is saturated with oxygen and carbon dioxide is released from the erythrocytes. The blood then carries oxygen throughout the body.