Which of the following incorrectly describes the similarities and differences between the secondary structures of proteins and DNA?

• A. Both proteins and DNA form helical structures.
• B. Proteins form alpha helices and beta sheets, while DNA forms a double helix.
• C. Hydrogen bonding stabilizes the secondary structures in both proteins and DNA.
• D. Proteins' secondary structure is entirely determined by the sugar-phosphate backbone, like DNA.

Answer: (D)