Answer:
carbon dioxide passes from the blood into the alveoli and is then exhaled. Oxygenated blood travels from the lungs through the pulmonary veins and the cycle goes on every time you breath or inhale you inhale oxygen into your blood cells.
Explanation:
Smoking
Bad cholesterol and really low hdl or good
High blood pressure or uncontrolled hypertension
Obesity
Uncontrolled stress or anger
:)
