Final answer:
The breaking down of complex organic compounds by the action of enzymes forming C₂H₅OH and CO₂ is called fermentation.
Step-by-step explanation:
The breaking down of complex organic compounds by the action of enzymes forming C₂H₅OH and CO₂ is called fermentation.
In fermentation, enzymes break down complex organic compounds, such as glucose, into simpler molecules like ethanol (C₂H₅OH) and carbon dioxide (CO₂). This process involves the catabolic breakdown of carbon compounds through the action of enzymes.
Therefore, the correct answer is a. fermentation.