This document discusses cigarettes and smoking. It defines a cigarette as a narrow cylinder containing nicotine and harmful chemicals that is usually packaged in groups of 20. Cigarettes are addictive because nicotine alters dopamine and noradrenaline levels in the brain, causing relaxation. The effects of smoking include gum disease, eye damage, increased risk of cancer and heart disease. The document suggests ways to quit smoking such as using nicotine replacements, avoiding triggers, exercising, and behavioral therapy.