Answer:
If your blood pH levels aren't regulated then your blood will be like acid and potentially be fatal.
Explanation:
Your body tries to maintain homeostasis so regulating blood pH levels is vital.
Because they are the same chemical reaction but reversed. Cellular respiration takes glucose (from nutrient/food) and oxygen (from atmosphere) in order to make CO2 (think about exhaling) and H20 (water).
(I don't remember this clearly so it may be wrong, i'll look into it and come back!)
It provides resources for the community but it destroys the environment under ground and reduces the minerals for future use.