Final answer:
The Krebs cycle is the cellular process during which pyruvic acid is broken down into carbon dioxide.
Step-by-step explanation:
The process during which pyruvic acid is broken down into carbon dioxide is the Krebs cycle (or citric acid cycle or tricarboxylic acid cycle). In glycolysis, a molecule of glucose is broken down into two molecules of pyruvate, which then enter the Krebs cycle in the presence of oxygen. In the Krebs cycle, pyruvate is further broken down and carbon dioxide is produced as a byproduct.