The main function of cellular respiration is to generate :

Options

A. `CO_2`
B. `O_2`
C. `ATP`
D. NADH

Explanation

### Step-by-Step Solution:

1. **Understanding Cellular Respiration**:
- Cellular respiration is a biochemical process where organisms convert glucose (sugar) into energy. This process is essential for all living organisms as it provides the energy required for various biological functions.

2. **Identifying the Products of Cellular Respiration**:
- During cellular respiration, glucose is broken down, and several byproducts are produced, including carbon dioxide and water. However, the primary focus of this process is the generation of energy.

3. **Recognizing the Energy Currency**:
- The energy produced during cellular respiration is stored in the form of ATP (Adenosine Triphosphate). ATP is often referred to as the "energy currency" of the cell because it is used to power various cellular activities.

4. **Differentiating Between Byproducts and Energy**:
- While carbon dioxide and water are byproducts of cellular respiration, they are not the main function of the process. Instead, they are waste products that are expelled from the organism.

5. **Conclusion**:
- The main function of cellular respiration is to generate ATP, which is crucial for the energy needs of the organism.

### Final Answer:
The main function of cellular respiration is to generate **ATP**.

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