Phosphoenol pyruvate (PEP) is the primary `CO_(2)` acceptor in

Options

A. `C_(3)`-plants
B. `C_(4)`-plants
C. `C_(2)`-plants
D. `C_(3) and C_(4)`-plants

Explanation

### Step-by-Step Solution:

1. **Understanding Phosphoenolpyruvate (PEP)**:
- Phosphoenolpyruvate (PEP) is a three-carbon molecule that plays a crucial role in the process of photosynthesis, specifically in the carbon fixation process.

2. **Identifying the Plants**:
- The question asks about the primary CO2 acceptor in different types of plants: C3, C4, C2, or both C3 and C4 plants.

3. **Role of PEP in C4 Plants**:
- PEP is primarily known as the CO2 acceptor in C4 plants. In these plants, PEP reacts with atmospheric CO2 to form oxaloacetate, which is a four-carbon compound.

4. **Process of CO2 Fixation**:
- In C4 plants, the CO2 is initially fixed into oxaloacetate in the mesophyll cells. This is the first stable compound formed during the process of carbon fixation in C4 photosynthesis.

5. **Adaptations in C4 Plants**:
- C4 plants have special adaptations, including dimorphic chloroplasts. These adaptations help in minimizing photo-respiratory losses, which can occur during photosynthesis.

6. **Conclusion**:
- Therefore, the primary CO2 acceptor, phosphoenolpyruvate (PEP), is found in C4 plants.

### Final Answer:
Phosphoenolpyruvate (PEP) is the primary CO2 acceptor in **C4 plants**.

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