Final answer:
NAD⁺H is produced in glycolysis and the Krebs cycle during cellular respiration, and is used to generate ATP in the electron transport chain.
Step-by-step explanation:
The stage(s) of cellular respiration that produce NAD⁺H are glycolysis and the Krebs cycle. In glycolysis, a small amount of NADH is produced when glucose is converted into two pyruvate molecules. This NADH is later used in the third stage to produce ATP. In the Krebs cycle, NADH is produced when pyruvate is further broken down and carbon dioxide is released.
Overall, the production of NAD⁺H in these two stages is important for the generation of ATP in the final stage of cellular respiration, known as the electron transport chain.