If a person smokes too much, it can affect his/ her respiratory system, because, he/ she will be able to inhale much carbon dioxide coming from the smoke, making his/ her lungs filter more carbon. If he/ she keeps smoking, his/her lungs may not function well because it has already acquired much carbon and other gases and it will affect other parts in the respiratory system.
If the respiratory system will function well anymore, the circulatory system will be greatly affected because the blood will not receive sufficient oxygen causing some cells to die out of not being able to undergo cellular respiration.