What is the active ingredient in cannabis responsible for its psychoactive effects?

The active ingredient in cannabis primarily responsible for its psychoactive effects is THC, specifically delta-9-tetrahydrocannabinol. This compound interacts with the endocannabinoid system in the human brain, producing the "high" associated with cannabis use. While CBD (cannabidiol) is another compound found in cannabis, it is non-psychoactive and does not create the same effects as THC.

While the choice that includes both THC and CBD suggests that both could contribute to the effects of cannabis, it is essential to understand that THC is specifically the compound that induces the psychoactive experiences. CBD is often noted for its therapeutic benefits without the intoxicating effects and may actually counteract some of the anxiety that THC can induce. Hence, the correct answer highlights the primary psychoactive ingredient rather than including non-psychoactive components.

In summary, the focus on THC as the primary psychoactive element encapsulates the core aspect of how cannabis affects the human brain, making it the correct choice.