Which of the following is responsible for maintaining the shape of the cell membrane? 

The lipid bilayer is the component of the cell membrane that helps to maintain its fluidity while also providing a selectively permeable barrier. It is composed of two layers of phospholipid molecules that have a hydrophobic (water-repelling) tail and a hydrophilic (water-attracting) head. This unique structure allows the membrane to regulate the passage of molecules in and out of the cell, while also maintaining its shape and integrity. Cholesterol is also present in the membrane and helps to maintain its fluidity by preventing the phospholipid tails from sticking together.