Facultative anaerobic bacteria are

Options

A. strictly anaerobes
B. anaerobes but can live aerobically
C. aerobes but can live anaerobically also
D. no one is correct

Answer

**Step-by-Step Solution:**

1. **Understanding the Terminology:**
- First, we need to understand the terms "aerobes" and "anaerobes."
- Aerobes are organisms that require oxygen for their survival and growth.
- Anaerobes are organisms that do not require oxygen and can survive in its absence.

2. **Differentiating Between Types of Anaerobes:**
- There are two main types of anaerobes:
- **Obligate Anaerobes:** These bacteria can only survive in environments devoid of oxygen. If exposed to oxygen, they will die.
- **Facultative Anaerobes:** These bacteria can survive in both the presence and absence of oxygen. They prefer to use oxygen for respiration when it is available, but can switch to fermentation when oxygen is not present.

3. **Analyzing the Options:**
- Now, let's analyze the options given in the question:
- **Option A:** Strictly anaerobes - This is incorrect because facultative anaerobes can survive in the presence of oxygen.
- **Option B:** Anaerobes but can live aerobically - This is also incorrect because while they can live aerobically, they are not strictly anaerobes.
- **Option C:** Aerobes but can live anaerobically - This is correct because facultative anaerobes prefer oxygen but can survive without it.
- **Option D:** No one is correct - This is incorrect since option C is correct.

4. **Conclusion:**
- The correct answer is **Option C:** Aerobes but can live anaerobically.