The Lichen grows on bare rock,
no earth, little sustenance,
a tenuous foothold to life.
It asks for sun and time
and grows, defeated, grows again.
It rains, it grows, summer drought comes,
it dies, to grow again with rain.
And when it dies it leaves a little behind.
Soil? Or is it the merest memory of Lichen
So.Mosses grow, a succession plant,
thicker, greener, richer
because of the poor precursor
which took a foothold where no other could.
The foregoing tells you that CO2 was drawn from the atmosphere to produce oxygen.