Essentiality of light in photosynthesis can be demonstrated by

Options

A. Molles half leaf experiment
B. Ganong screen
C. Inverted funnel experiment
D. KOH solution

Answer

**Step-by-Step Solution:**

1. **Understanding Photosynthesis**:
- Photosynthesis is the process by which green plants synthesize food using light energy, primarily from sunlight. The basic equation for photosynthesis is:
\[ 6CO_2 + 6H_2O + light \ energy \rightarrow C_6H_{12}O_6 + 6O_2 \]
- This indicates that carbon dioxide and water are converted into glucose and oxygen in the presence of light.

2. **Identifying the Role of Light**:
- Light is essential for the photosynthesis process as it provides the energy required for the conversion of carbon dioxide and water into glucose.

3. **Experiments to Demonstrate Light's Essentiality**:
- Various experiments can demonstrate the necessity of light in photosynthesis. Two notable experiments are:
- **Moll's Half-Leaf Experiment**: This experiment shows the necessity of carbon dioxide, not light.
- **Ganong's Screen Experiment**: This experiment specifically demonstrates the essentiality of light in photosynthesis.

4. **Ganong's Screen Experiment**:
- In this experiment, a part of the leaf is covered with a black strip or cloth, preventing light from reaching that area.
- The plant is then exposed to sunlight for a period of time.
- After exposure, the leaf is tested for the presence of starch (a product of photosynthesis).
- The area covered by the black cloth does not show any starch, indicating that photosynthesis did not occur in that area due to the absence of light.

5. **Conclusion**:
- The Ganong's screen experiment conclusively demonstrates that light is essential for photosynthesis, as the area that received no light did not produce starch.

**Final Answer**: The essentiality of light in photosynthesis can be demonstrated by Ganong's screen experiment.

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