A relative clause modifies a noun, similar to an adjective. It provides additional information about the noun and typically begins with a relative pronoun such as "who," "whom," "whose," "which," or "that."
The other statements are not accurate:
- A relative clause cannot stand alone as a complete sentence; it is dependent on the main clause for context.
- A relative clause does not begin with a noun; it begins with a relative pronoun.
Therefore, the correct statement is that a relative clause modifies a noun, similar to an adjective.