Here's why:
* Noun: A noun is a word that names a person, place, thing, or idea. Examples: *dog*, *tree*, *happiness*, *city*.
* Pronoun: A pronoun is a word that takes the place of a noun. Examples: *he*, *she*, *it*, *they*, *we*.
Examples:
* The dog barked loudly. ( *dog* is a noun)
* He barked loudly. (*he* is a pronoun, replacing the noun "dog")
Let me know if you'd like more examples!