Chemosynthetic bacteria obtain energy from

Options

A. sun
B. infrared ray
C. organic substances
D. inorganic chemicals

Explanation

To answer the question "Chemosynthetic bacteria obtain energy from," we can follow these steps:

### Step 1: Understand the definition of chemosynthetic bacteria
Chemosynthetic bacteria are organisms that obtain energy through the oxidation of inorganic substances. They do not rely on sunlight or organic compounds for energy.

### Step 2: Analyze the options provided
The options given are:
1. Sun
2. Infrared ray
3. Organic substance
4. Inorganic chemicals

### Step 3: Evaluate each option
- **Sun**: Chemosynthetic bacteria do not use sunlight as a source of energy. This option can be eliminated.
- **Infrared ray**: Similar to sunlight, infrared rays are not utilized by chemosynthetic bacteria for energy. This option can also be eliminated.
- **Organic substance**: Chemosynthetic bacteria do not derive energy from organic substances. This option is not correct.
- **Inorganic chemicals**: This is the correct option. Chemosynthetic bacteria obtain energy by oxidizing inorganic chemicals, such as hydrogen sulfide, ammonia, or ferrous iron.

### Step 4: Conclusion
Based on the analysis, the correct answer is **inorganic chemicals**. Chemosynthetic bacteria are unique in that they were among the first organisms on Earth and utilize inorganic substances to produce energy.

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

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