Name the three carbon compound converted during respiration? How is it converted to products in absence, presence, and lack of oxygen?

The answer is pyruvate. In the absence of oxygen in anaerobic respiration, the pyruvate is converted to lactic acid in animals and ethanol in plants. However, in the presence of oxygen, the pyruvate enters the Krebs cycle after being converted to Acetyl CoA. Pyruvate is an intermediate product of glycolysis.