Answer:
<em>Noun.</em>
Explanation:
First we need to remember that adjectives are parts of speech which stand beside a noun and modify it. ( for example: big city)
Adjective clause is a type of a dependent clause that consist of a relative pronoun (which connects clause with the word we are describing), subject and a verb - they all together serve as an adjective. So, just like adjectives, they also modifies nouns.
E.g. The cookies <em>that my Grandma bakes</em> are very tasty.
