Select ALL amino acids with aromatic side chains.

### Why this is right - **Phenylalanine**: its side chain contains a phenyl ring. - **Tyrosine**: its side chain contains an aromatic ring with a hydroxyl group. - **Tryptophan**: its side chain contains an aromatic fused-ring system. ### The concept Aromatic amino acids contain ring systems with delocalized electrons. Their side chains differ in polarity: phenylalanine is strongly hydrophobic, while tyrosine and tryptophan have additional features that increase their capacity for interactions. ### The other options - **Glycine**: its side chain is hydrogen, so it has no aromatic ring. ### Terms - **Hydrophobic**: tending to avoid interaction with water. ### Remember The standard aromatic amino acids are phenylalanine, tyrosine, and tryptophan.