Honestly i think it is expository because it does explain and go into detail while answering a question well that is what the word means.
It is also called a dative case..represented by <em>dat or d</em> ..it indicates that noun to whom something is given..like <em>she gave Jess a book..</em> here Jess is dat or prepositional case..
My answer is danger b/c the wind is trying to pull itself off the ledge to save itself even while being depressed