Question

which term describes the three - dimensional structure of an enzyme? secondary primary elementary tertiary

Explanation:

Enzymes are proteins. The primary structure is the linear sequence of amino - acids. The secondary structure involves local folding patterns like alpha - helices and beta - sheets. The tertiary structure is the three - dimensional structure formed by further folding of the secondary - structure elements, giving the enzyme its overall 3D shape. There is no "elementary" structure term in protein structure hierarchy.

Answer:

D. tertiary