Photosynthesis requires

Options

A. Chlorophyll
B. `CO_2`
C. water
D. All of these

Answer

**Step-by-Step Solution:**

1. **Understanding Photosynthesis**: Photosynthesis is the process by which plants convert light energy into chemical energy, specifically in the form of glucose. This process primarily occurs in the chloroplasts of plant cells.

2. **Identifying the Requirements**: The main requirements for photosynthesis include:
- **Light Energy**: This is usually provided by sunlight.
- **Chlorophyll**: This green pigment found in plants is essential for absorbing light energy.
- **Carbon Dioxide (CO2)**: This gas is taken in from the atmosphere through the stomata of leaves.
- **Water (H2O)**: This is absorbed by the roots from the soil.

3. **The Photosynthesis Equation**: The general equation for photosynthesis can be written as:
\[ 6CO_2 + 6H_2O + \text{light energy} \rightarrow C_6H_{12}O_6 + 6O_2 \]
This shows that carbon dioxide and water react in the presence of light energy and chlorophyll to produce glucose and oxygen.

4. **Conclusion**: Therefore, the requirements for photosynthesis are:
- Light energy
- Chlorophyll
- Carbon dioxide
- Water

5. **Final Answer**: Since all of the above components are essential for the process of photosynthesis, the correct answer to the question "Photosynthesis requires" is option 4: all of these.

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