The isotope of carbon used extensively for studies in photosynthesis is

Options

A. `.^(13)C`
B. `.^(14)C`
C. `.^(15)C`
D. `.^(16)C`

Answer

To answer the question regarding the isotope of carbon used extensively for studies in photosynthesis, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Isotopes of Carbon**: Carbon has several isotopes, including Carbon-12 (C-12), Carbon-13 (C-13), Carbon-14 (C-14), and Carbon-15 (C-15). Each isotope has a different number of neutrons.

2. **Understand the Role of Isotopes in Research**: Isotopes, particularly radioactive ones, are often used in scientific studies to trace processes and reactions. In the context of photosynthesis, researchers use isotopes to track the movement and transformation of carbon during the process.

3. **Focus on Radioactive Isotopes**: Among the isotopes listed, Carbon-14 (C-14) is a radioactive isotope. It is commonly used in various biological and ecological studies due to its ability to decay and provide measurable data over time.

4. **Link C-14 to Photosynthesis Studies**: C-14 has been extensively used in studies related to photosynthesis, particularly in understanding the Calvin cycle. The Calvin cycle is a crucial part of photosynthesis where carbon fixation occurs, and C-14 helps trace the pathway of carbon atoms in this cycle.

5. **Conclude with the Correct Answer**: Based on the information gathered, the isotope of carbon that is used extensively for studies in photosynthesis is Carbon-14 (C-14).

### Final Answer:
The isotope of carbon used extensively for studies in photosynthesis is **Carbon-14 (C-14)**.

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