Final answer:
Addiction refers to a strong dependency on a substance, activity, or behavior. Nicotine is a highly addictive chemical found in tobacco. Emphysema is a chronic lung disease caused by smoking cigarettes.
Step-by-step explanation:
1. Addiction:
Addiction refers to the strong physical or psychological dependency on a substance, activity, or behavior. For example, smoking tobacco can lead to nicotine addiction.
2. Nicotine:
Nicotine is a highly addictive chemical found in tobacco. It acts as a stimulant and is responsible for the addictive effects of smoking.
3. Emphysema:
Emphysema is a chronic lung disease characterized by the damage to the air sacs in the lungs. Smoking cigarettes can lead to emphysema due to the breakdown of lung tissues by the toxic substances in tobacco smoke.