Read and learn!- Granny:hippy:

Radioactive tobacco
Radioactive tobacco

Progression from marijuana use to daily smoking and nicotine dependence
Erowid.org: Erowid Reference 6951 : Progression from marijuana use to daily smoking and nicotine dependence in a national sample of U.S. adolescents : Timberlake DS, Haberstick BC, Hopfer CJ, Bricker J, Sakai JT, Lessem JM, Hewitt JK

Cannabis Smoke and Cancer: Assessing the Risk
Cannabis Smoke and Cancer: Assessing the Risk - NORML

Cannabis and tobacco smoke are not equally carcinogenic
Cannabis and tobacco smoke are not equally carcinogenic

Smoking Marijuana Does Not Cause Lung Cancer
US: Web: Study: Smoking Marijuana Does Not Cause Lung Cancer