Glycophorin A is a glycoprotein that extends across the red blood cell membrane. The portion of the polypeptide that extends across the membrane bilayer contains 19 amino acid residues and is folded into a alpha helix. The interior of the bilayer includes long acyl chains that are nonpolar. Which of the 20L-amino acids would you expect to find among those in the portion of the polypeptide that traverses the bilayer?