Which statement best describes the basic structure of the cell membrane and its contribution to selective permeability?

Which statement best describes the basic structure of the cell membrane and its contribution to selective permeability?

• A. The cell membrane is a rigid protein sheet with no lipid components.
• B. The lipid bilayer is impermeable to all substances, with no diffusion across.
• C. The cell membrane is a phospholipid bilayer but lacks cholesterol or proteins, making it highly permeable to ions.
• D. The cell membrane is a phospholipid bilayer with hydrophobic tails inside and hydrophilic heads outside, containing proteins, cholesterol, and carbohydrates; the hydrophobic core restricts polar molecules; small nonpolar molecules diffuse freely, while ions and larger polar molecules require channels or transporters to cross.

Answer: (D)