Question

what defines a noun? a word that changes/modifies a noun 1 a word that expresses an emotion 2 a word that represents a person, place, or thing 3

Explanation:

In linguistics, a noun is defined as a word that represents a person, place, or thing. Options 1 and 2 describe adjectives and interjections respectively.

Answer:

C. A word that represents a person, place, or thing