`NH_(3)` released from

Options

A. photorespiration
B. dark respiration
C. CAM
D. all of these

Answer

To determine from which process NH3 (ammonia) is released, let's analyze the options provided:

1. **Photorespiration**:
- Photorespiration is a process that occurs when the enzyme RuBisCO fixes oxygen instead of carbon dioxide during photosynthesis, especially under conditions of high oxygen and low carbon dioxide. This process leads to the production of ammonia (NH3) as a byproduct. Therefore, NH3 is released during photorespiration.
- **Conclusion**: This option is correct.

2. **Dark Respiration**:
- Dark respiration is a metabolic process that occurs in the absence of light. During this process, glucose is broken down to release energy, and carbon dioxide is produced as a waste product. NH3 is not produced in this process.
- **Conclusion**: This option is incorrect.

3. **CAM (Crassulacean Acid Metabolism)**:
- CAM is a photosynthetic adaptation found in some plants, where CO2 is taken up at night and stored as malate, which is then used during the day for photosynthesis. This process does not involve the release of NH3.
- **Conclusion**: This option is incorrect.

Based on the analysis, the correct answer is that NH3 is released from **photorespiration**.

### Step-by-Step Solution:
1. **Identify the processes listed**: Photorespiration, Dark Respiration, and CAM.
2. **Analyze Photorespiration**: Understand that it involves oxygen fixation and leads to NH3 production.
3. **Analyze Dark Respiration**: Recognize that it produces carbon dioxide, not NH3.
4. **Analyze CAM**: Note that it is a photosynthetic process that does not produce NH3.
5. **Conclude**: The only process that releases NH3 is photorespiration.