Answer:
Verb.
Explanation:
In the given sentence, the italicized word is "wound" which can be taken in two ways. One is a noun that refers to a physical injury while the second is a verb that means to inflict pain or hurt to a person.
But in the sentence, the word is used to refer to the act of tying in a spiral pattern. This act of tying is an action verb, thereby making it a verb. The word "wound" as used in the sentence is the past tense form of the verb "wind".
So, the correct answer is a verb.
It would be a subordinate cause, for it can't stand on its own. Think about it: Since early this morning. What happened since early morning? Since it doesn't provide that information, it wouldn't be able to be an independent cause.
Also, I don't believe that the sentence is grammatically correct :)