Answer:
What makes this true is that they are not safe because when doctors over prescribe some people get addicted causes some people to take more than need and to OD
Explanation:
Pretty sure the answer is D
Answer: A
Explanation: The blood–air barrier (alveolar–capillary barrier or membrane) exists in the gas exchanging region of the lungs. It exists to prevent air bubbles from forming in the blood, and from blood entering the alveoli. ... The barrier is permeable to molecular oxygen, carbon dioxide, carbon monoxide and many other gases.
D. They carry oxygenated blood to the lungs to be pumped to the heart then around the body. Pulmonary has to do with the lungs
