D. living things as a reservoir
Explanation:
The 47,XXY karyotype of Klinefelter syndrome spontaneously arises when paired X chromosomes fail to separate (nondisjunction in stage I or II of meiosis, during oogenesis or spermatogenesis
Calcium in the teeth provides appropriate pH levels in the mouth.
Glycolysis is the first step in the respiration pathway. The amount of oxygen available after glycolysis determines whether the rest of the reaction is aerobic (Krebs Cycle and Electron Transport Chain) or anaerobic (Fermentation).
