Yup, it starts off as an observed effect, then gets documented enough to where it shows up in studies, and then doctors are willing to prescribe it for “off label” use, then trials are run to rigorously test for that effect, until the medical health authorities agree that there’s a strong enough scientific basis to use as a treatment for that condition to where it is approved for that use.

It’s just charcoal filtering (which is a process used in many, many food and drink processes), but one source of industrial quantities of charcoal comes from charred bones (after the proteins are extracted making soup or whatever).

City planners in the 60s favored male trees for this reason. Then air pollution and a warming climate, mixed with all that extra pollen, gave rise to a huge increase in seasonal allergies in urban areas.

Yes but that’s because the nursery has already grafted the branches of a known-to-be-tasty cultivar onto that tree before putting it up for sale.