Which of the following correctly describes facultative anaerobes?

• A. They produce energy exclusively through anaerobic respiration.
• B. They require oxygen to survive and cannot perform fermentation.
• C. They can only survive in environments devoid of oxygen.
• D. They can survive with or without oxygen, using fermentation or aerobic respiration.

Answer: (D)

Verified step by step guidance

1. Understand the term 'facultative anaerobes': These are organisms that can survive in both oxygen-rich and oxygen-poor environments.
2. Facultative anaerobes have the ability to switch between aerobic respiration and fermentation based on the availability of oxygen.
3. In the presence of oxygen, facultative anaerobes will typically use aerobic respiration, which is more efficient in terms of energy production.
4. In the absence of oxygen, these organisms can switch to fermentation, allowing them to continue producing energy without oxygen.
5. Recognize that facultative anaerobes are versatile in their metabolic processes, which allows them to adapt to varying environmental conditions.