Exhalation occurs when the diaphragm relaxes, returning to its dome form and pushing air out of your lungs. This rhythmic contraction and rest are important for preserving regular respiratory and ensuring adequate oxygen source to your body.Thi?t b? ho?t ??ng không s? d?ng ?i?n n?ng nên giúp ti?t ki?m ???c m?t kho?n chi phí r?t l?n.These muscle