Both hemp and marijuana are Cannabis Sativa L. plants.  Within the United States, the 2018 Farm Bill defined hemp as “any Cannabis Sativa L. that tested below 0.3%THC on a dry weight basis.” (2018 Farm Bill) Marijuana is therefore defined as Cannabis Sativa L. with more than 0.3% THC.

Cannabinoids are naturally occurring chemical compounds found in the Cannabis plant that interact with our body. Cannabinoids can be made by plants–phytocannabinoids–or by our bodies–endocannabinoids. Humans are not alone in having these cannabinoid receptors! Nearly all animals have an endocannabinoid system. (The Endocannabinoid System of Animals)

THC, or Delta 9 tetrahydrocannabinol as it is known chemically, is the most psychoactive of the more than 113 major and minor cannabinoids that science has uncovered within the Cannabis plant.