Answer:
Adjective subordinate clause
Explanation:
A subordinate clause, also called a dependent clause, is a clause that can't stand by itself as a simple sentence, unlike an independent clause. Subordinate clauses provide additional information and can function as a noun, an adjective, or an adverb.
<em>The dog </em><em><u>that chewed up my new shoes</u></em><em> </em><em>is named Oscar. </em>
In the given sentence we have an adjective subordinate clause because it additionally describes the noun that comes before it - <em>the dog</em>. Adjective clauses begin with a relative pronoun or a relative adverb, in this case, the pronoun <em>that</em>.