Chemosynthetic bacteria obtain energy from

Options

A. Sunlight
B. infra red rays
C. organic substances
D. inorganic chemicals.

Explanation

### Step-by-Step Solution:

1. **Understanding Chemosynthetic Bacteria**:
- Chemosynthetic bacteria are organisms that can produce their own food using inorganic substances. Unlike plants that use sunlight for photosynthesis, these bacteria derive energy from chemical reactions involving inorganic materials.

2. **Energy Source**:
- The energy that chemosynthetic bacteria use comes from exergonic chemical reactions. These reactions release energy during the process of breaking down inorganic substances.

3. **Oxidation Process**:
- The specific type of reaction that chemosynthetic bacteria utilize involves the oxidation of inorganic substances. This means that these bacteria oxidize certain inorganic compounds to derive energy.

4. **Formation of Organic Food**:
- Using the energy obtained from these oxidation reactions, chemosynthetic bacteria convert inorganic raw materials into organic compounds. This process is essential for their survival and growth.

5. **Energy Storage**:
- The chemical energy obtained from the oxidation reactions is often stored in the form of ATP (adenosine triphosphate), which is a common energy currency in biological systems.

6. **Conclusion**:
- Therefore, chemosynthetic bacteria obtain energy from inorganic chemicals. This distinguishes them from other organisms that rely on sunlight or organic substances for energy.

### Final Answer:
Chemosynthetic bacteria obtain energy from **inorganic chemicals**.

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