Final answer:
The fatty acid tails of phospholipids are hydrophobic and are located inside the phospholipid bilayer, away from water.
Step-by-step explanation:
The fatty acid tails of phospholipids are hydrophobic and are found in the interior of the phospholipid bilayer. Phospholipids are composed of a hydrophilic head that includes a phosphate-containing group attached to a glycerol molecule, and two hydrophobic tails, each containing a fatty acid chain. In the structure of the cell membrane, the amphipathic nature of these molecules allows them to form a bilayer where the hydrophilic heads face outward towards the aqueous environment, and the hydrophobic tails face inward, away from water.