Explained looks at Marijuana and examines its use throughout history from the use of the drug in Ancient China to modern day. It looks at how the domestication of hemp led to selection for strong fiber but also for strong psychoactive potency. It looks at the biology of the plant and how female plant produce stronger doses of cannabinoids. It also looks at wide variety of cannabis strains that have been produced through selective breeding and how there is lack of consistency in labeling of marijuana varieties. It looks at legalization and how heavy users are influencing the market.