Oxygen was not present in the primitive atmosphere of the earth. The 21% O2 of today's air were formed in the course of evolution by photosynthesis of algae, this made life on the mainland possible. Leer más.
Oxygen was not present in the primitive atmosphere of the earth. The 21% O2 of today's air were formed in the course of evolution by photosynthesis of algae, this made life on the mainland possible. Leer más.