Final answer:
Phospholipids have a hydrophilic head and hydrophobic tails, with the correct answer being b) Hydrophilic, hydrophobic. These molecules form a bilayer in cell membranes with the hydrophilic heads facing outwards and the hydrophobic tails inward.
Step-by-step explanation:
Phospholipids, the major component of cell membranes, contain a hydrophilic polar head and two hydrophobic nonpolar tails. The correct answer is b) Hydrophilic, hydrophobic. Phospholipids are amphipathic molecules with a hydrophilic 'head' consisting of a phosphate group and glycerol molecule, and hydrophobic 'tails' composed of two long fatty acids. In a cell membrane, these phospholipids align themselves into a bilayer, with the hydrophilic heads facing the aqueous environments inside and outside the cell, and the hydrophobic tails facing each other, away from water.