There are many other bee species that can sting Humans and survive, but the European honeybee has a barbed stinger, so it cannot remove the stinger once it's stung. In attempting to remove the stinger the bee will rupture its lower abdomen and then die....
Not sure you got the oxygen part right. But I can say that since trees and animal breath each others exhaust, they won’t both thrive due to atmospheric oxygen concentration.
Why are honeybee stingers barbed?
There are many other bee species that can sting Humans and survive, but the European honeybee has a barbed stinger, so it cannot remove the stinger once it's stung. In attempting to remove the stinger the bee will rupture its lower abdomen and then die....
Why were dinosaurs huge?
I mean, why evolution selected dinosaurs to become that huge?