Which one does not evolve oxygen

Options

A. Photosynthetic bacteria
B. Blue Green algae
C. Green algae
D. Autotrophic plants.

Answer

To solve the question "Which one does not evolve oxygen?", we can follow these steps:

### Step 1: Understand the Types of Photosynthesis
- There are two main types of photosynthesis: oxygenic and anoxygenic. Oxygenic photosynthesis produces oxygen as a byproduct, while anoxygenic photosynthesis does not.

### Step 2: Identify Photosynthetic Organisms
- Photosynthetic organisms can be broadly categorized into:
- **Cyanobacteria (Blue-green algae)**: These perform oxygenic photosynthesis, using water (H2O) as a hydrogen donor, leading to the release of oxygen.
- **Green Algae and Autotrophic Plants**: These also perform oxygenic photosynthesis, resulting in oxygen evolution.
- **Photosynthetic Bacteria (e.g., Green and Purple Sulfur Bacteria)**: These perform anoxygenic photosynthesis, using hydrogen sulfide (H2S) instead of water, which does not produce oxygen.

### Step 3: Analyze the Options
- From the above information, we can conclude that:
- **Cyanobacteria**: Evolve oxygen (oxygenic photosynthesis)
- **Green Algae**: Evolve oxygen (oxygenic photosynthesis)
- **Autotrophic Plants**: Evolve oxygen (oxygenic photosynthesis)
- **Photosynthetic Bacteria (Green and Purple Sulfur Bacteria)**: Do not evolve oxygen (anoxygenic photosynthesis)

### Step 4: Conclusion
- Therefore, the correct answer to the question "Which one does not evolve oxygen?" is the **Photosynthetic Bacteria**, specifically the green and purple sulfur bacteria.

### Final Answer
- The organism that does not evolve oxygen is the **Photosynthetic Bacteria** (Green and Purple Sulfur Bacteria).

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