Final answer:
A semipermeable membrane allows some particles through the cell membrane.
Step-by-step explanation:
The best definition for semipermeable is: Allows some particles through the cell membrane. A semipermeable membrane or cell membrane is one that selectively allows certain molecules or ions to pass through while blocking others. For example, in a cell, semipermeable membranes control the movement of substances in and out of the cell, allowing only certain molecules or ions to pass through.
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