Energy is required for :

Options

A. active transport
B. facilitated transport
C. diffusion
D. all of these

Explanation

**Step-by-Step Solution:**

1. **Understanding Energy in Cells**:
- Energy is crucial for the functioning of cells. It is primarily produced in the mitochondria, which are known as the "powerhouse of the cell." The energy produced is in the form of ATP (adenosine triphosphate).

2. **Analyzing the Options**:
- The question asks for processes that require energy. We will evaluate each option provided.

3. **Option 1: Active Transport**:
- Active transport is a process where substances move from an area of low concentration to an area of high concentration. This movement against the concentration gradient requires energy, specifically in the form of ATP. Therefore, this option is correct.

4. **Option 2: Facilitated Transport**:
- Facilitated transport occurs due to a difference in concentration on either side of the membrane. It allows substances to pass through the membrane without the need for energy. Hence, this option is incorrect.

5. **Option 3: Diffusion**:
- Diffusion is the movement of particles from an area of high concentration to an area of low concentration. This process is also known as passive transport and does not require energy. Therefore, this option is incorrect.

6. **Option 4: All of the Above**:
- Since only active transport requires energy and the other processes do not, this option is also incorrect.

7. **Conclusion**:
- The only process that requires energy is active transport. Therefore, the correct answer is **Option 1: Active Transport**.

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