_____ in carbon dioxide in your red blood cells, which causes _____ in pH, causes your breathing to speed up. See Concept 42.6 (Page) View Available Hint(s) _____ in carbon dioxide in your red blood cells, which causes _____ in pH, causes your breathing to speed up. See Concept 42.6 (Page) A decrease ... a drop An increase ... a rise An increase ... a drop A decrease ... a rise Actually, it is the rise and fall of oxygen, not carbon dioxide, that controls breathing.