Fill in the blanks
______ separates the contents of a cell from its surrounding medium.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a term that describes what separates the internal contents of a cell from the external environment.

2. **Identifying the Key Concept**: In cellular biology, the structure responsible for this separation is known as the cell membrane.

3. **Defining the Cell Membrane**: The cell membrane, also known as the plasma membrane, is a biological membrane that separates and protects the interior of all cells from the outside environment.

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