Question

part a
the alpha - helix is an example of the ______ level of protein structure.
options: tertiary, secondary, primary, quaternary

Explanation:

Protein structure has levels: primary (amino acid sequence), secondary (local folding like alpha - helix, beta - sheet), tertiary (overall 3D), quaternary (multiple subunits). Alpha - helix is local folding, so it's secondary.

Answer:

B. secondary