Answer: The correct answer is A) Lipids.
Cell membrane is present around the cytoplasm of all cells of the living organisms, which separates the interior of the cell from its external environment. It is primarily made up of two layer of phospholipids, therefore called phospho-lipid bilayer. Thus, the central bilayer is formed by the lipids in the cell membrane.
It is a selectively permeable membrane. This means that it regulates the transport of substances in and outside the cell.
Thus, option A) Lipids is the right answer.
