Answer:
tobacco
Step-by-step explanation:
Smoking is terrible for your teeth. You can get cavities, abscesses, overgrown gums, and tooth loss. Nicotine is a heavy stimulant, so without it you can get insomnia and feel awful without it, if you're a very regular smoker. Smoking is terrible for your lungs, and the body works as a system, if your lungs start failing, you can most definitely get a heart attack.
You can definitely get COPD from smoking. Smoking is terrible for your lungs, because of all the toxins that get released into your body. It can ruin your immune system, weaken your airways and most definitely kill you.