<span>your answer is cranial cavity </span>
Organic molecules can form in a reducing atmosphere. Good luck.
The answer is c. oxygen.
Cellular respiration includes glycolysis, link reaction, Krebs cycle, and electron transport chain (ETC), in that order. The main function of ETC is a production of ATP. In this series of oxidation-reduction reactions, electrons from the previous stages of cellular respiration are taken and transported to the oxygen which is the final acceptor of electrons. As the result, water and ATP are produced.
