Question

which macromolecule forms a double layer as the primary structure of cell membranes?
fats
oils
phospholipids
steroids

Explanation:

Cell membranes have a phospholipid - bilayer structure. Phospholipids have a hydrophilic head and hydrophobic tails. The hydrophilic heads face the aqueous environments inside and outside the cell, while the hydrophobic tails are in the interior of the bilayer. Fats, oils, and steroids do not form the primary structure of cell membranes in this way.

Answer:

phospholipids