Final answer:
Selectively permeable refers to a characteristic of cell membranes that only allow certain substances to pass through while restricting others.
Step-by-step explanation:
Selectively permeable refers to a characteristic of cell membranes, allowing only certain substances to pass through while restricting others. This is crucial for maintaining homeostasis and controlling what enters or exits the cell. For example, small molecules like oxygen and carbon dioxide can freely diffuse across the membrane, while larger molecules or ions may require specific transport proteins.
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