(note: some textbooks state that up to 36 atp molecules are produced in this phase of cellular respiration. in reality, some energy is lost in the process due to the cost of transporting molecules and imperfect membranes.)

extend your thinking: when you think of the word “respiration,” you might think about the process of breathing, which is actually called ventilation. (the respiratory system consists of the windpipe, lungs, etc.)
how is breathing related to cellular respiration? (hint: think about both the inputs and the outputs of cellular respiration.)