Human and Animal need to breathe to stay alive, but different animals may have different breathing structures, for example frog used moist skin to help them breath.
Human need air to breathe. When we inhale (take in) and exhale (let out) air. We can notice that our chest moves up and down. This movement is called the rate of breathing. As we inhale, the air is taken through the nose, down the windpipe into the lungs. This air contains more oxygen. Alternatively, as we exhale, the chest moves in causing the chest to contract. The air inside the lungs then flows out from the lung to the windpipe and then out through the nose. This air contains more carbon dioxide.
