Final answer:
The two main types of fermentation are alcohol fermentation, which produces ethanol and carbon dioxide, and lactic acid fermentation, which produces lactic acid. These processes allow for ATP production in the absence of oxygen and recycle NADH to NAD+. Therefore, the correct option is b.
Step-by-step explanation:
The two main types of fermentation are alcohol fermentation and lactic acid fermentation. Fermentation is a process that makes ATP without oxygen, involving only glycolysis. In alcohol fermentation, yeasts and some bacteria convert pyruvate into alcohol and carbon dioxide, while in lactic acid fermentation, certain bacteria and muscle cells convert pyruvate into lactic acid. Both types allow the recycling of NADH into NAD+ so glycolysis can continue to produce ATP under anaerobic conditions.
Alcohol Fermentation
In alcoholic fermentation, organisms like yeast convert pyruvate into ethanol and carbon dioxide. This process is utilized in making bread, wine, and biofuels.
Lactic Acid Fermentation
Lactic acid fermentation involves the conversion of pyruvate to lactic acid. This type of fermentation is used by muscle cells during intense exercise and by bacteria in the production of yogurt.