Which of the following is the only group of organisms capable of
using inorganic compounds as source of energy ?

Options

A. Fungi
B. Chemo autotrophs
C. Both the above
D. None of the above

Answer

**Step-by-Step Solution:**

1. **Understand the Question**: The question asks which group of organisms can use inorganic compounds as a source of energy.

2. **Analyze the Options**: The options provided are:
- Fungi
- Chemoautotrophs
- Both of the above
- None of the above

3. **Evaluate Option 1 - Fungi**:
- Fungi are not autotrophs; they are classified as saprotrophs.
- They obtain their nutrients from dead and decaying organic matter rather than using inorganic compounds for energy.
- Therefore, fungi cannot be the correct answer.

4. **Evaluate Option 2 - Chemoautotrophs**:
- Chemoautotrophs are a group of organisms that can produce their own food using inorganic compounds.
- They utilize chemical reactions involving inorganic substances (like hydrogen sulfide) to generate energy.
- This makes them capable of using inorganic compounds as a source of energy, confirming that this is the correct answer.

5. **Evaluate Option 3 - Both of the Above**:
- Since fungi cannot use inorganic compounds for energy, this option is incorrect.

6. **Evaluate Option 4 - None of the Above**:
- Since we have identified that chemoautotrophs can use inorganic compounds, this option is also incorrect.

7. **Conclusion**: The only group of organisms capable of using inorganic compounds as a source of energy is **chemoautotrophs**.

**Final Answer**: Chemoautotrophs

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