Oxygen enters the capillaries and what from the capillaries passes into the lungs?

blood rich in oxygen enters the lungs through the pulmonary artery in where the alveoli within the lungs exchange carbon dioxide and oxygen so the carbon dioxide leaves your body.

Hope this helps a bit

halogen, any of the six nonmetallic elements that constitute group 17 (group viia) of the periodic table. the halogen elements are fluorine (f), chlorine (cl), bromine (br), iodine (i), astatine (at), and tennessine (ts).