The human breath occurs constantly, drawing oxygen through the lungs and into the bloodstream to nourish the body's cells and organs. It contracts and expands the lungs through the soft trachea and bronchi, providing vital energy for the heart while also regulating body temperature, strengthening the immune system, and removing waste through exhaled air. Essential yet involuntary, the human breath sustains life by oxygenating the blood and reinvigorating the brain.