Final answer:
The plasma membrane is composed of lipids arranged in a bilayer layer with the hydrophilic heads facing the intra- and extracellular fluid.
Step-by-step explanation:
The plasma membrane is composed of lipids arranged in a bilayer layer with the hydrophilic heads facing the intra- and extracellular fluid. The hydrophilic heads of the lipids are attracted to water, so they face the watery intracellular and extracellular environments. The hydrophobic tails, on the other hand, are repelled by water and face each other in the middle of the bilayer.
Learn more about Structure of the plasma membrane