Which organelle forms the outermost layer in animal cells?

Options

A. Mitochondria
B. Plasma membrane
C. Cell wall
D. Nuclear membrane

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the organelle that forms the outermost layer in animal cells. We need to identify the correct organelle from the provided options.

2. **Evaluating the Options**:
- **Option 1: Mitochondria**: Mitochondria are known as the powerhouse of the cell and are involved in cellular respiration. They are not the outermost layer of the cell.
- **Option 2: Plasma Membrane**: The plasma membrane, also known as the cell membrane, is indeed the outermost layer of animal cells. It is selectively permeable, meaning it controls what enters and exits the cell.
- **Option 3: Cell Wall**: The cell wall is a rigid outer layer found in plant cells, not in animal cells. Therefore, this option is incorrect for animal cells.
- **Option 4: Nuclear Membrane**: The nuclear membrane surrounds the nucleus of the cell but is not the outermost layer of the entire cell.

3. **Conclusion**: After evaluating all the options, the correct answer is Option 2: Plasma Membrane, as it is the outermost layer in animal cells.

**Final Answer**: The organelle that forms the outermost layer in animal cells is the **Plasma Membrane**.

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