C and D structures function mainly in transport. Hence, option D is correct.
The membrane structures that function in active transport eg. integral proteins.
A major role of the plasma membrane is transporting substances into and out of the cell.
The plasma membrane is selectively permeable, allowing only certain substances to pass through.
Proteins embedded within the plasma membrane helps to move hydrophilic, polar molecules into the cell.
Hence, option D is correct.
Learn more about the structure's function in active transport here:
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