A) For it does not require a life long commitment, and it is not C) because it can be any substance not just tobacco!
Thus your answer is A) gradually but completely withdrawing substances from use !
Have a happy life !
:D <span />
Answer:
A. Vena cava
Explanation:
The aorta can't be the answer because it is the largest artery in the human body and it carries oxygenated blood. The pulmonary artery carries deoxygenated blood into the lungs for oxygenation. The pulmonary veins transfer oxygenated blood from the lungs to the heart. And lastly, the vena cava is the right answer and it returns deoxygenated blood back into the heart.
Answer:
D
Explanation:
as air passes through your system it is filtered, warmed and moistened because of you need that to breath.
