What is true for photolithotrophs?

Options

A. Obtain energy from radiations and hydrogen from organic compounds
B. Obtain energy from radiations and hydrogen from inorganic compounds
C. Obtain energy from organic compounds
D. Obtain energy from inorganic compounds

Answer

### Step-by-Step Solution:

1. **Definition of Photolithotrophs**:
- Photolithotrophs are organisms that utilize light as their primary energy source.
- They obtain hydrogen and electrons from inorganic compounds.

2. **Breakdown of the Term**:
- The term "photolithotroph" can be broken down into two parts:
- "Photo" refers to light.
- "Litho" refers to inorganic compounds.

3. **Energy and Hydrogen Source**:
- Photolithotrophs harness energy from light (radiation).
- They do not derive hydrogen from organic compounds; instead, they rely on inorganic sources.

4. **Analyzing the Options**:
- Option A states that they obtain energy from radiation and hydrogen from organic compounds. This is incorrect because photolithotrophs do not use organic compounds for hydrogen.
- Option B states that they obtain energy from radiation and hydrogen from inorganic compounds. This is correct as it aligns with the definition of photolithotrophs.
- Option C states that they obtain energy from organic compounds, which is incorrect.
- Option D also states they obtain energy from organic compounds, which is incorrect.

5. **Conclusion**:
- The correct statement about photolithotrophs is that they obtain energy from radiation and hydrogen from inorganic compounds. Therefore, the correct answer is Option B.