Completar frases SCB2/2014 Learning Activity 2Versión en línea Free access to incredible Science learning resources for kids 8-12. http://dreameryappy.wix.com/sciencecuriobox por Admin ScienceCurioBox 1 windpipe body respiration blood thin vessels oxygen burn photosynthesis decomposition Air release is made of many gases . Nitrogen , oxygen and carbon dioxide are some of these gases . Oxygen is required by living things during as it helps energy from our food . Without oxygen , fire cannot ! Carbon dioxide is needed by plants to conduct . Carbon dioxide is also produced during . When we respire , the air we breathe in travels from our nose , down our , into our lungs . The air sacs in our lungs have walls and are rich in . The in the air is absorbed and transported to the various parts of our through the blood vessels .