The third one is the product of cellular respiration
Ethonal is produced during b. Alcohol fermentation that converst sugars into ethanol.
Answer:
It enters the citric acid cycle and associates with a 4-carbon molecule, forming citric acid, and then through redox reactions regenerates the 4-carbon molecule.
Explanation:
Acetyl-CoA(2C) associates with oxalacetate(4C) to form citric acid(6C). Then through redox reactions, CO2 molecules result from decarboxylation (COOH becomes R-(R1)CH-R2). And through dehydrogenation H2 molecules are incorporated in NADH+ in FADH2, resulting in the 4-carbon molecule at the beginning (oxalacetate). That's why it's called a cycle(Kreb's cycle or citric acid cycle)