In the passage beginning with “with enchanting murmurs” and ending with “flight of stairs” the house gets described as Gatsby and Daisy make their way up the stairs. The description is in such a way that it creates a feeling of solemness to emphasize the importance of the event of making their way up the stairs.
mr. ford sleeps on a feather mattress in his apartment.
the answer to the given sentence above would be a complex sentence. what makes it complex is that, it contains an independent and a dependent clause. the clauses are connected by a subordinating conjunction which is the word "although". hope this answers your question.