cigarettes and chewing tobacco
Breathing tubes in your lungs swell and it causes a lot of coughing and soreness in your chest. You get a disease called bronchitis.
From chewing tobacco, sores can develop can form on your gums- looks like leathery, white patches. Also, you can develop "hairy tongue".
Nicotine is the addictive drug in tobbaco. It makes you crave it. Then it's very dangerous because when you get addicted to it, the more you smoke the more deadly it gets.
You get plaque build up on the inside walls of the arteries, it can cause deadly heart attacks and strokes.
Smoking causes cancer. You get malignant growths or tumors, caused by abnormal and uncontrolled cell division.