Concept:The cell membrane is a selectively permeable barrier made of a lipid bilayer with associated proteins.
Explanation:The membrane is primarily composed of a double layer of lipids, called a lipid bilayer.
Proteins are embedded within or attached to this lipid bilayer.
These membrane proteins help in transport, communication, and structural support.
Because both lipids and proteins are present, the membrane is not made of lipids alone or proteins alone.
Cytosol is the fluid inside the cell, not a structural component of the membrane.
Answer:B. contains lipids and protein