.\'atural proteins are composed primarily of 20 u-ainino acids Which one of the following
statements is true for any of these amino acids in a solution opr 1.51”
(A) Only the amino group is ionized.
(Bl Only the carboxylic acid group is ionized.
(C) Both amino and carboxylic acid groups are ionized.
(D) Both amino and carboxylic acid groups are neutral.