Facultative anaerobes

Options

A. Cannot use oxygen for growth and are even harmed by it
B. Cannot use oxygen for growth, but tolerate the presence of it
C. Are aerobes which can grow without oxygen
D. Die when given aerobic condition

Answer

### Step-by-Step Solution:

1. **Understanding Facultative Anaerobes**:
- Facultative anaerobes are organisms that can grow in both the presence and absence of oxygen. They primarily use aerobic respiration when oxygen is available but can switch to anaerobic respiration or fermentation when oxygen is not available.

2. **Analyzing the Options**:
- **Option 1**: "Cannot use oxygen for growth and are even harmed by it."
- This statement describes obligate anaerobes, not facultative anaerobes. Therefore, this option is incorrect.

- **Option 2**: "Cannot use oxygen for growth but tolerate the presence of it."
- This option also describes organisms that are not facultative anaerobes. It is more aligned with some types of anaerobes. Thus, this option is incorrect.

- **Option 3**: "Are aerobics which can grow without oxygen."
- This accurately describes facultative anaerobes. They can grow in the presence of oxygen (aerobic conditions) and can also survive and grow without it (anaerobic conditions). Therefore, this option is correct.

- **Option 4**: "Die when given aerobic condition."
- This statement describes obligate anaerobes, which cannot survive in the presence of oxygen. Hence, this option is incorrect.

3. **Conclusion**:
- After evaluating all the options, the correct answer is **Option 3**: "Are aerobics which can grow without oxygen."