> every breath we take has elements of the same breath as every human who ever lived (excluding some currently living ones, due to diffusion rates, but eventual

> every breath we take has elements of the same breath as every human who ever lived (excluding some currently living ones, due to diffusion rates, but eventually...) Is it conceivable that some of the oxygen and nitrogen, etc, in the atmosphere today wasn’t present in the atmosphere, say, 40,000 years ago due to it being bound up in minerals or biological matter?