Answer: a. Lipids/Fatty Acids
Explanation:
Cells are packed with and surrounded by water, the structure of cell membranes is defined by the way membrane lipids perform in a watery (aqueous) environment. The lipid bilayer constitutes the primary structure of all cell membranes. The lipids in cell membranes combine two properties in a single molecule: each lipid has a hydrophilic (“water-soluble”) head and a hydrophobic (“water-insoluble”) tail.
