Inner core, outer core, mantle and crust
Isn't this Chem?
a non metal and a metal
a metal transfers electrons to the non metal
the non metal gains electrons and becomes an anion (a negatively charges ion)
and the metal loses electrons and becomes a cation (a positively charged ion)
During normal breathing, the brain is stimulated to breath with increasing acidity as a result of CO2 concentration from basic metabolic processes. The brain is quite selfish and only really wants to maintain it's pH which should be at a range of 7.3-7.45, and will not tolerate any decrease.
In patients who have a chronic respiratory disorder with things like COPD. The brain has become accustomed to excessive acidic content, and is now stimulated by the Hypoxic drive or by low oxygen content.