A cell is surrounded by an extremely thin, flexible membrane. Why is the membrane selectively permeable?
A. It allows all substances to pass through, making it easier to absorb nutrients.
B. It allows all organic substances to pass through, but excludes all inorganic substances that could be harmful.
C. It does not allow any substances to pass through as they could damage the cell.
D. It allows some substances to pass through and excludes others based on size, polarity, and other factors.
Answer: D
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