The plasma membrane found in both prokaryotic and eukaryotic cells is composed of a/an , which is semipermeable and controls the flow of molecules into and out of the cell.

the answer is a phospholipid bilayer

it's called phospholipid because it's made of a group of lipids that has a phosphate group and bilayer because it's made of hydrophilic heads that are exposed to the solution and hydrophobic tails that are directed inwards