This little machine, which also knows how to recycle and reuse all its parts in a sustainable “green” way, keeps the nitrogen in balance for the whole planet.
As an exercise, count the number of lucky breaks that had to occur for the evolutionary story to work.
Hemoglobin is well known as the molecule that transfers oxygen in blood, but its precursor, heme, is lesser known.
Finely tuned and exquisitely engineered, this system gave our ancestors enough oxygen not only to stay alive but to thrive in the face of grave challenges.
James Lovelock has pointed out that atmospheric levels of oxygen much above about 25 percent, let alone 30 percent, would cause raging conflagrations today.