How does gas exchange happen

Gas exchange happens when air passes into the lungs through a tube called the trachea, (which contains rings of cartilage that prevent the trachea from collapsing during inhalation.) The trachea now split into two smaller tubes called the bronchi with one passing to each lung, further into the lunges the bronchi sub-divide into smaller tubes called bronchioles and the bronchioles end in tiny air sacs called alveoli