The drug cannabis, commonly known as marijuana, is produced from parts of the cannabis plant, primarily the cured flowers and gathered trichomes of the female plant. The major active chemical compound tetrahydrocannabinol, commonly referred to as THC, has psychoactive and medicinal effects when consumed, usually by smoking or ingestion. Cannabis has been consumed by humans for thousands of years; in the 20th century there was an upswing in the use of cannabis for recreational and religious purposes.
The possession, use, or sale of psychoactive cannabis products became illegal in many parts of the world in the early 20th century. Since then, while some countries have intensified the enforcement of cannabis prohibition, others have reduced the priority of enforcement to the point of de facto legality. Cannabis remains illegal in the vast majority of the world's countries.

Marijuana and Teenagers - Designed by a high school in Australia. Offers information on different types of marijuana, characteristics of marijuana, and the effects of the drug on teenagers.
Marijuana's Adverse Effects - Answers questions about becoming dependent, common side effects, and physical effects.
Marijuana: Facts for Teens - From the National Institute on Drug Abuse, comprehensive information about marijuana and its effects.
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