Which of the following statement is correct ?

Options

A. All bacteria are heterotrophic
B. Bacteria are either heterotrophic, chemoautotrophic
C. Bacteria are either heterotrophic, chemoautotrophic or photoautotrophic
D. Bacteria are either chemoautotrophic or photoautotrophic

Answer

To determine which statement about bacteria is correct, let's analyze each option step by step:

1. **Understanding Bacteria and Nutrition**:
- Bacteria are classified based on their mode of nutrition into two main categories: autotrophs and heterotrophs.
- Autotrophic bacteria can synthesize their own food from inorganic substances, while heterotrophic bacteria cannot and rely on other organisms for their nutrition.

2. **Types of Autotrophic Bacteria**:
- Autotrophic bacteria are further divided into:
- **Photoautotrophs**: These bacteria derive their energy from light.
- **Chemoautotrophs**: These bacteria obtain energy from the oxidation of inorganic substances.

3. **Analyzing the Options**:
- **Option A**: "All bacteria are heterotrophic."
- This statement is incorrect because not all bacteria are heterotrophic; some are autotrophic.
- **Option B**: "Bacteria are either heterotrophic, chemoautotrophic."
- This statement is incomplete as it excludes photoautotrophic bacteria.
- **Option C**: "Bacteria are either heterotrophic, chemoautotrophic or photoautotrophic."
- This statement is correct as it includes all types of bacteria based on their nutritional modes.
- **Option D**: "Bacteria are either chemoautotrophic or photoautotrophic."
- This statement is also incomplete as it excludes heterotrophic bacteria.

4. **Conclusion**:
- The correct statement is **Option C**: "Bacteria are either heterotrophic, chemoautotrophic or photoautotrophic."