Cellular respiration (oxidative phosphorylation) is a fundamental biological process universally understood as the primary mechanism for generating ATP and regenerating ADP in humans, making it a matter of established textbook knowledge that requires no citation.
The claim that cellular respiration is the ultimate source of ATP and ADP regeneration in humans represents a foundational biological truism taught in introductory science. Under Step 0, statements that are trivially true by definition or direct observation are classified as common knowledge, requiring no citation and no papers attached.