Select the incorect statement w.r.t photosyntheseis

Options

A. Anabolic , endergonic and redox process
B. Physico- chemical process using light energy to drive the synthesis of organic compounds
C. of the total world's photosynthesis , 90% is carried out by fresh water plants
D. Annually ` 4 xx 10^(13)` kg of carbon is fixed through photosythesis in biosphere

Answer

To solve the question of selecting the incorrect statement with respect to photosynthesis, we will analyze each of the four statements provided:

### Step-by-Step Solution:

1. **Analyze the First Statement:**
- Statement: "Photosynthesis is an anabolic, endergonic and redox process."
- Explanation: Photosynthesis is indeed an anabolic process because it builds larger molecules (glucose) from smaller ones (carbon dioxide and water). It is also endergonic, as it requires energy (from sunlight) to proceed, and it involves redox reactions (oxidation and reduction) as water is split to release oxygen.
- **Conclusion:** This statement is correct.

2. **Analyze the Second Statement:**
- Statement: "Photosynthesis is a physical chemical process using light energy to drive the synthesis of organic compounds."
- Explanation: This statement accurately describes photosynthesis, as it uses light energy to convert carbon dioxide and water into glucose (an organic compound).
- **Conclusion:** This statement is correct.

3. **Analyze the Third Statement:**
- Statement: "Of the world's total photosynthesis, 90% is carried out by freshwater plants."
- Explanation: This statement is incorrect. While freshwater plants do contribute to photosynthesis, a significant portion is carried out by algae (especially phytoplankton) in aquatic environments. In fact, most of the photosynthesis in the world is attributed to marine algae, not just freshwater plants.
- **Conclusion:** This statement is incorrect.

4. **Analyze the Fourth Statement:**
- Statement: "Annually, 4 x 10^13 kilograms of carbon is fixed through photosynthesis in the biosphere."
- Explanation: This statement is supported by scientific research and is considered accurate. The amount of carbon fixed through photosynthesis is indeed estimated to be around this figure.
- **Conclusion:** This statement is correct.

### Final Answer:
The incorrect statement with respect to photosynthesis is: **"Of the world's total photosynthesis, 90% is carried out by freshwater plants."**

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