“Of the team” is the prepositional phrase. It is used to clarify what David is captain of.
I would say parentheses but if you are on about a thing before I would say brakets
I am sort of puzzled on this particular question; however, I think I solved it. Okay, so the text starts with explaining the benefits of coffee, then it proceeds to explain the negative affects of consuming coffee. Transition words like <em>on the other hand</em> are commonly used when contrasting ideas. Hence, I believe the correct answer is c. contrast.