The correct answer is: (B) erythropoietin (EPO) – increases white blood cell production.
Explanation:
Erythropoietin is a hormone secreted by the kidney when dealing to cellular hypoxia (low oxygen content on body tissues) to stimulate red blood cell production. This is because red blood cells are the ones that transport oxygen to every tissue in the body.
These are things that won't be going away. Natural gasses and fossil fuels will likely run out someday or become much harder to find. When you use these sources of energy, they won't be going away and therefore will be sustainable because we can always continue using them.
