what important gas do we take in when we breathe

The important gas we take in when we breathe is oxygen. Oxygen is essential for the survival and functioning of our body's cells, as it is used in cellular respiration to produce energy. When we inhale, we take in about 21% oxygen from the air, which then passes into the blood through the lungs. This oxygen-rich blood is circulated to all the cells in the body, where oxygen is used to generate energy. In the process, carbon dioxide, a waste product from the cells, is carried back to the lungs and exhaled out.