Pyruvate, the product of glycolysis, is converted to acetyl-CoA, the starting material for the citric acid cycle, by the pyruvate dehydrogenase complex. Acetyl-CoA donates its acetyl group to the four-carbon compound oxaloacetate to form the six-carbon citrate.
Pyruvate is the first intermediate compound in the Krebs cycle.
<u>Explanation:</u>
Pyruvate is the product formed from the glycolysis. In the Krebs cycle the compound pyruvate is converted into acetyl CoA.
This is carried out into three steps. The 'Krebs cycle' is also called as the 'citric acid cycle' due to this reason.
Multiple molecules of this pyruvic acid are used in yielding the high energy for the process. These chemical reactions are carried out by all anaerobic organisms.
Answer: A mutagen is a chemical compound or form of radiation that causes mutations, which of course means a change in the dna of a cell. So, your answer would be C) an environmental agent that changes DNA.