During respiration ...... combines with oxygen in the cells and produces `CO_(2)` and water.

Options

A. sucrose
B. fructose
C. glucose
D. galactose

Explanation

**Step-by-Step Solution:**

1. **Understanding Respiration**: Respiration is a biochemical process in which cells convert glucose and oxygen into energy, carbon dioxide, and water.

2. **Identifying the Reactants**: The primary reactant in cellular respiration is glucose, which is a simple sugar that serves as a key energy source for cells.

3. **Chemical Equation**: The overall chemical reaction for cellular respiration can be represented as:
\[ C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{Energy} \]
Here, \(C_6H_{12}O_6\) represents glucose, and \(O_2\) represents oxygen.

4. **Products of Respiration**: During this process, glucose combines with oxygen to produce carbon dioxide (\(CO_2\)), water (\(H_2O\)), and energy, which is essential for various cellular functions.

5. **Conclusion**: Therefore, the substance that combines with oxygen in the cells during respiration is glucose.

**Final Answer**: Glucose

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