PGA as the first `CO_(2)` fixation product was discovered in photosynthesis of

Options

A. bryophyte
B. gymnosperm
C. angiosperm
D. alga

Explanation

To solve the question regarding the discovery of PGA (phosphoglycerate) as the first CO₂ fixation product in photosynthesis, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding PGA**:
- PGA stands for phosphoglycerate, which is a three-carbon compound formed during the process of photosynthesis.

2. **Identifying the Scientist**:
- The scientist who discovered PGA as the first product of CO₂ fixation is Melvin Calvin.

3. **Recognizing the Context**:
- Melvin Calvin conducted his research on the process of photosynthesis, specifically focusing on the fixation of carbon dioxide.

4. **C3 Plants**:
- The fixation of CO₂ leading to the formation of PGA occurs primarily in C3 plants. This is because the Calvin Cycle, where PGA is produced, is also known as the C3 cycle.

5. **Experimental Method**:
- Calvin used radioactive carbon (C¹⁴) in his experiments to trace the path of carbon during photosynthesis, which helped him identify PGA as the first stable product of CO₂ fixation.

6. **Conclusion**:
- Therefore, the correct answer to the question is that PGA as the first CO₂ fixation product was discovered in the photosynthesis of algae.

### Final Answer:
PGA as the first CO₂ fixation product was discovered in the photosynthesis of **algae**.

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