Moll's half-leaf experiment proves that___ is essential for photosynthesis to take place

Options

A. chlrophyll
B. `CO_(2)`
C. Light
D. `H_(2)O`

Answer

**Step-by-Step Solution:**

1. **Introduction to Moll's Experiment**: Moll conducted an experiment to determine whether carbon dioxide is essential for photosynthesis.

2. **Setup of the Experiment**: He took a leaf from a plant and divided it into two halves. One half was submerged in a beaker containing a caustic potash (potassium hydroxide) solution, while the other half was left exposed to the air.

3. **Carbon Dioxide Absorption**: The beaker with the submerged half was designed to absorb carbon dioxide from the environment. The caustic potash solution absorbed the carbon dioxide present in the beaker.

4. **Exposure to Sunlight**: The entire setup was placed in sunlight to ensure that photosynthesis could potentially occur in the exposed half of the leaf.

5. **Testing for Starch**: After a few days, Moll tested both halves of the leaf for the presence of starch using iodine. The exposed half turned black, indicating the presence of starch, while the submerged half remained yellow, indicating no starch was present.

6. **Conclusion**: Moll concluded that carbon dioxide is essential for photosynthesis because the exposed half of the leaf, which had access to carbon dioxide from the air, produced starch, while the submerged half did not, as it was deprived of carbon dioxide.

**Final Answer**: Moll's half-leaf experiment proves that **carbon dioxide** is essential for photosynthesis to take place.

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