Final answer:
Proteins stabilize their tertiary structure through disulfide linkages, hydrophobic interactions, and hydrogen bonding, with each type of interaction contributing to the protein's overall stability and shape.
Step-by-step explanation:
Three things that help stabilize the tertiary structure of proteins include disulfide linkages, hydrophobic interactions, and hydrogen bonding. Disulfide linkages are covalent bonds that form between the sulfur atoms of two cysteine amino acids, providing significant stability to the protein structure. Hydrophobic interactions occur when nonpolar amino acid side chains cluster away from water, leading to a conformation that minimizes their exposure to water, thus stabilizing the protein's three-dimensional form. Lastly, hydrogen bonding between various parts of the polypeptide chain further contributes to the stabilization of the tertiary structure.