What is a noun clause as a modifier?

What is a noun clause as a modifier?

A noun clause as a modifier is a type of clause that functions as an adjective or adverb to modify a noun or pronoun in a sentence. It acts as a single unit and includes a subject and a verb. Noun clauses can be introduced by words such as "that," "whether," "if," "who," "whom," "whose," "what," "when," "where," "why," or "how." These clauses provide additional information about the noun or pronoun they modify and can answer questions such as "what kind," "which one," "how much," "how many," or "what happened."