The solar system is considered a natural system because it was made and controlled by natural forces, meaning, it was never influenced with human creations. It is considered as one of the products of the phenomenon of the physical world. Hope this answer helps you.
Explanation:
Vestigiality is the retention during the process of evolution of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on comparison with homologous features in related species.
Answer:
not enough clean oxygen being produced for us to breathe, loss of habitat for countless species causing them to possibly go extinct.
I believe you use the pH scale with comparing acids and bases.