Identifying Polar Amino Acids

Consider the role of amino acids in biochemical processes, particularly focusing on the structure and properties of amino acids in proteins. Each amino acid has unique characteristics that dictate its function within protein structures. In proteins, the sequence and types of amino acids can significantly affect the protein's folding, stability, and interaction with other molecules.

Which of the following amino acids contains a side chain that can participate in hydrogen bonding and is classified as polar due to its ability to interact with water and other polar molecules?