The primary source of the effects produced by consuming Cannabis comes from their abundance of Cannabinoids. There are over 100 different Cannabinoids found in the Cannabis plant, most of them located in the female flowers. Each Cannabinoid has a different effect on your body and mind.
Alone, many of them may not have much effects at all. It is when they are combined in a full spectrum solution that the powerful effects of Cannabis can be utilized to its fullest potential.