What is the main psychoactive chemical found in marijuana that contributes to its effects?

The main psychoactive chemical found in marijuana is THC, or tetrahydrocannabinol. THC is responsible for producing the "high" associated with marijuana use, as it interacts with the body's endocannabinoid system, particularly by binding to the CB1 receptors in the brain. This interaction can lead to various effects, such as alterations in mood, perception, and cognition.

While cannabinoids is a broader term that encompasses THC as well as other compounds found in cannabis, it does not specifically identify the psychoactive component. Cannabinol is another cannabinoid found in marijuana, but it is non-psychoactive and usually formed by the degradation of THC. CBD (cannabidiol) is also a key compound in cannabis, known for its medical benefits without the psychoactive effects. Nevertheless, it is THC that primarily contributes to the psychoactive effects of marijuana, making it the correct answer to the question.