1. It refers specifically to the smoke that a smoker directly inhales.

 2 It is the smoke that comes out of the lighted end of a cigarette or pipe and more dangerous than mainstream smoke

3. Smoke left for a long time on sofa, beddings, pillow and other objects. It settles along with dust and can last for months and still contains harmful chemicals and carcinogens.

4. Sometimes called common tobacco, which is preferred for producing present day cigarettes.

5. Chemical/ addictive drug found in tobacco products like cigarettes which is a poisonous stimulant and narrows our veins and arteries. It can also damage our heart by forcing it to work faster and harder, slow our blood and reduce oxygen to our feet and hands.