6. About the respiration system, which of the following statement is TRUE?
(A) Alveoli is the place where gas exchange occurs
(B) In the capillaries of alveoll, CO2 diffuses into the blood and O2 diffuses into the air
(C)During inhalation, Iung volume increases as the rib muscle contracts and diaphragm m relaxes
(D) The breathing control center is located in the hypothalamus