What amount of carbon is fixed in the biosphere through photosynthesis annually ?

Options

A. `4xx10^(13)g`
B. `3xx10^(4)kg`
C. `10^(4)kg`
D. `4xx10^(13)kg`

Answer

**Step-by-Step Solution:**

1. **Understanding Photosynthesis**: Photosynthesis is the process by which plants and algae convert carbon dioxide and water into glucose and oxygen using sunlight. This process consists of two main reactions: the light reactions and the dark reactions.

2. **Chemical Equation of Photosynthesis**: The overall reaction can be summarized by the equation:
\[ 6 \text{CO}_2 + 6 \text{H}_2\text{O} \xrightarrow{\text{light}} \text{C}_6\text{H}_{12}\text{O}_6 + 6 \text{O}_2 \]
Here, carbon dioxide (CO₂) is fixed into glucose (C₆H₁₂O₆), and oxygen (O₂) is released.

3. **Annual Carbon Fixation**: The total amount of carbon fixed in the biosphere through photosynthesis annually is a theoretical value. According to scientific data, this amount is approximately \(4 \times 10^{13}\) kg.

4. **Evaluating Options**: The options provided are:
- \(4 \times 10^{-13}\) g
- \(3 \times 10^{-4}\) g
- \(10^{-4}\) kg
- \(4 \times 10^{13}\) kg

Among these, \(4 \times 10^{13}\) kg is the correct answer.

5. **Conclusion**: Therefore, the amount of carbon fixed in the biosphere through photosynthesis annually is \(4 \times 10^{13}\) kg.