Cigarettes contain many compounds are non-what about the 4000, there kinds of carcinogens are not less than 42 kinds of harmful chemicals is important.
What's included cigarette smoking, with about 4000 species of various compounds are carcinogenic, no less than 42 different kinds of harmful substances is important.
Cigarettes contain anything rooms have various compounds is about 4000 type. There are no less than 42 carcinogen species. Some kinds of harmful substance is the key.