Final answer:
The hydrophobic region of the cell membrane functions as a selective barrier, while the hydrophilic region has specific functions such as transport, recognizing other cells, and binding to other cells.
Step-by-step explanation:
The correct answer is d) Hydrophobic region; hydrophilic region. The hydrophobic region of the cell membrane, which is made up of the fatty acid tails of the phospholipid bilayer, functions as a selective barrier, preventing the passage of water-soluble molecules. On the other hand, the hydrophilic region of the cell membrane, which is made up of the phosphate groups of the phospholipid bilayer and the exposed polar heads of the integral proteins, has specific functions such as transport, recognizing other cells, and binding to other cells.