15) which type of molecule makes up the double layer of a cell membrane? a) carbohydrate b) lipid c) nucleic acid d) protein

B) lipid is the correct answer.

Explanation:

The cell is made up of a bilayer of phospholipids which is a type of lipid.

Phospholipids are the abundant kind of lipid located in the cell membrane.

The lipid double layer is a common component of all cell membranes.

 It is composed of two components, a hydrophilic head, and a hydrophobic tail.

The hydrophilic head is composed of phosphate and glycerol.

The hydrophobic tail is composed of fatty acids.

Thus lipid type of molecule makes up the double layer of a cell membrane.