Many molecules can move briefly across the membrane without any requirement of energy and special membrane proteins. This is called _______.

Options

A. active transport
B. passive transport
C. facilitated diffusion
D. All of these

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the process through which many molecules can move across the cell membrane without the need for energy or special membrane proteins.

2. **Identifying Key Terms**:
- "Move across the membrane"
- "Without any requirement of energy"
- "Without special membrane proteins"

3. **Reviewing Transport Mechanisms**: There are different mechanisms through which substances can cross cell membranes:
- **Passive Transport**: This process does not require energy and can occur without the assistance of special proteins.
- **Active Transport**: This process requires energy (usually in the form of ATP) to move molecules against their concentration gradient.
- **Facilitated Diffusion**: This is a type of passive transport that requires specific proteins (carrier proteins) to help move molecules across the membrane.

4. **Determining the Correct Answer**: Since the question specifies that the movement occurs without energy and without special proteins, the correct answer is **Passive Transport**.

5. **Final Answer**: Therefore, the answer to the question is **Passive Transport**.

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