Final answer:
Cellular respiration is used more often than fermentation in metabolically versatile organisms. Cellular respiration is efficient and produces a larger amount of ATP, while fermentation is less efficient and produces a smaller amount of ATP. Fermentation is used when there is a scarcity of oxygen.
Step-by-step explanation:
In organisms that are metabolically versatile, the process used more often is cellular respiration.
Cellular respiration is the process that converts glucose and oxygen into carbon dioxide, water, and ATP. It is an efficient way to produce energy because it can generate a large amount of ATP.
In contrast, fermentation is less efficient and produces a smaller amount of ATP. It is used by organisms when there is a scarcity of oxygen. Fermentation involves the breakdown of glucose without the use of oxygen, and it produces lactic acid or ethanol as byproducts.