THIS TYPE OF RELATIONSHIP IS CALLED "COMMENSALISM"
The air that we breathe in is an example of solid solution
Embryology, the study of the development of the anatomy of an organism to its adult form, provides evidence for evolution as embryo formation in widely-divergent groups of organisms tends to be conserved. ... Another form of evidence of evolution is the convergence of form in organisms that share similar environments.
Guanine and adenine, structure-wise, are purines.
