Question

localized folding patterns within a polypeptide chain, such as alpha - helices and beta - pleated sheets, constitute a proteins: primary structure. secondary structure. tertiary structure.

Explanation:

Protein structure levels are defined by different folding patterns. The primary structure is the linear sequence of amino - acids. Secondary structure involves local folding patterns like alpha - helices and beta - pleated sheets due to hydrogen bonding. Tertiary structure is the overall 3 - D shape from further folding.

Answer:

B. Secondary structure