Identify the error in the following sentence: All government representatives must keep in contact with his or her constituents.

The sentence "All government representatives must keep in contact with his or her constituents" contains a singular pronoun "his or her" that refers back to the plural noun "representatives." When a subject is plural, the pronouns used to refer to it should also be plural to maintain agreement in number.

In this case, since "government representatives" is plural, the correct pronoun usage would be "their" instead of "his or her." Using "his or her" creates a mismatch, leading to confusion about whether the sentence is addressing one representative or multiple representatives. Thus, the presence of a plural antecedent alongside a singular pronoun constitutes an error in the sentence structure.