Shirley went for a run. During her run, her body was creating energy so that she could go a longer distance. Which step of cellular respiration converts each of her glucose molecules into pyruvic acid?

Glycolysis is the first stage of cellular respiration, where one glucose molecule is broken down into two molecules of pyruvic acid. The citric acid cycle and electron transport chain occur later, while phosphorylation is a process rather than the stage that converts glucose into pyruvic acid. So the correct choice is glycolysis.

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