Identify which sentence this is: The woman *who one the cookie competition* is my mother.

Subordinate Clause
Adjectival Clause
Independent Clause
Adverbial Clause

I would say it's Subordinate.

Yes. It's also an adjective clause.

http://www.chompchomp.com/terms/subordinateclause.htm

:D Thanx again!

You're welcome.

You are correct! The sentence "The woman who won the cookie competition is my mother" contains a subordinate clause. A subordinate clause is a type of dependent clause that cannot stand alone as a complete sentence and functions to provide additional information or clarify the main clause. In this case, the subordinate clause "who won the cookie competition" acts as an adjective, as it modifies the noun "woman" by providing more information about her. Great job!