Which of the Following Statements About Amino Acids Is INCORRECT

Which of the following statements about amino acids is INCORRECT?

A) A turn or kink in a protein is more likely to be induced by a proline than by a glycine.
B) The bridge between cysteines, which connects parts of a protein, is a stable but noncovalent interaction.
C) At typical cellular pH, the R groups of basic amino acids are positively charged.
D) Not every amino acid is asymmetric.
E) The more glycines that are found in a polypeptide's primary sequence, the more flexible the backbone of that polypeptide.