It serves as both reactant and a product in the photosynthetic process of higher plants

Options

A. `CO_2`
B. `O_2`
C. `H_(2)O`
D. glucose

Answer

### Step-by-Step Solution:

1. **Understanding Photosynthesis**: Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose, using carbon dioxide and water as raw materials.

2. **Photosynthetic Equation**: The general equation for photosynthesis can be represented as:
\[ 6 \, \text{CO}_2 + 12 \, \text{H}_2\text{O} + \text{light energy} \xrightarrow{\text{chlorophyll}} \text{C}_6\text{H}_{12}\text{O}_6 + 6 \, \text{O}_2 + 6 \, \text{H}_2\text{O} \]
Here, carbon dioxide (CO₂) and water (H₂O) are the reactants, and glucose (C₆H₁₂O₆) and oxygen (O₂) are the products.

3. **Identifying Reactants and Products**: In the equation, we can see that:
- **Reactants**: 6 molecules of carbon dioxide and 12 molecules of water.
- **Products**: 1 molecule of glucose, 6 molecules of oxygen, and 6 molecules of water.

4. **Analyzing Water's Role**: Water (H₂O) is involved in both the reactant and product sides of the equation:
- As a **reactant**, water is absorbed by the roots of the plant from the soil.
- As a **product**, water is released during the photosynthetic process, specifically from the splitting of water molecules during the light-dependent reactions.

5. **Conclusion**: Therefore, water serves as both a reactant and a product in the photosynthetic process of higher plants.

### Final Answer:
Water acts as both a reactant and a product in the photosynthetic process of higher plants.

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