The biological part. You know, the binding receptors that the chemicals act upon. They haven't changed much in the last several million years, and certainly even less in the last hundred or so.
You know, the binding receptors that the chemicals act upon.
Oh, like the CB1 and CB1 2 cannabinoid receptors present on the surface of cells in different parts of the central nervous system?
You're right, they're still around so we haven't "evolved" them out of ourselves after several millennia, much less a mere century.
What was your point again?