Answer:
Adverb Clause
<em><u>While</u></em><em><u> the sailboat bobbed at anchor</u></em> we watched the stars come out.
Explanation:
Adverb Clause-a clause that functions as an adverb in a sentence. It always starts with a subordinating conjunction.
Example: <em><u>Even</u></em><em><u> if I take the test</u></em>, my grades won't change.
Noun Clause-a clause that acts as a noun.
For example, I am not interested in <em><u>whatever Anthony says.</u></em>
Adjective Clause-a clause that is used to describe a noun in a sentence.
For example, the guy <em><u>who claimed to be a genius</u></em> didn't even make it to the top list.