Answer
"Lipid bilayers are macromolecules that are made up mostly of phospholipid subunits" is true
Work Step by Step
Phospholipids are a type of lipid that consist of a hydrophilic tail and a phosphate head that makes it an excellent macromolecule for membranes and barriers in the cell. Lipid bilayers are composed of a channel of phospholipids that allow or restrict the passing of materials needed or discarded by the cell.