Which of the Following Is Characteristic of An $\alpha$ -Helix?
A)Hydrogen Bonds Between -NH Groups on One Part of

Which of the following is characteristic of an $\alpha$ -helix?

A) Hydrogen bonds between -NH groups on one part of the chain and C=O groups on nearby amino acids cause the protein to coil with the amino acids' R groups pointing outward.
B) Dipole-dipole interactions between polar side groups in one part of the chain and C=O or -NH groups on nearby amino acids cause the protein to coil with the amino acids' R groups pointing outward.
C) London forces between hydrophobic regions in the amino acid sequence cause the protein to coil up in order to have hydrophilic regions of the chain point outward.
D) Single-strand proteins interact via hydrogen bonds, forming coils in which polar side groups point outward.
E) Side-by-side zigzag chains of amino acids held together by hydrogen bonds aggregate to form a coiled structure held together by intermolecular forces.