Moll's Half leaf experiment proves that

Options

A. light is essential for photosynthesis
B. `CO_2` is essential for photosynthesis
C. `O_2` is released during photosynthesis
D. Chlorophyll is essential for photosynthesis

Answer

### Step-by-Step Solution:

1. **Understanding the Experiment**: Moll's Half Leaf Experiment is designed to investigate the factors necessary for photosynthesis. The experiment involves a potted plant that has been kept in the dark for a few days to deplete its starch reserves.

2. **Preparation of the Leaf**: After the plant is de-starched, a leaf is taken, and one half of it is treated with a potassium hydroxide (KOH) solution. KOH absorbs carbon dioxide (CO2) from the air, effectively removing it from the environment of that half of the leaf.

3. **Exposure to Light**: The entire leaf (with one half treated with KOH) is then exposed to light for a certain period, allowing photosynthesis to occur in the half that was not treated with KOH.

4. **Testing for Starch**: After the exposure to light, the leaf is tested for starch using iodine solution. The presence of starch indicates that photosynthesis has occurred, while the absence indicates that it has not.

5. **Results**: The upper half of the leaf (the one not treated with KOH) gives a positive starch test, indicating that photosynthesis took place there. In contrast, the lower half (the one treated with KOH) gives a negative starch test, indicating that photosynthesis did not occur.

6. **Conclusion**: The experiment demonstrates that carbon dioxide (CO2) is essential for photosynthesis. While the experiment also indirectly supports the necessity of light and chlorophyll, the primary conclusion drawn from Moll's Half Leaf Experiment is that CO2 is crucial for the process of photosynthesis.

### Final Answer:
The correct conclusion from Moll's Half Leaf Experiment is that **CO2 is essential for photosynthesis**.

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