Which element is part of a business letter? subject
audience
brief introduction
sender’s address

Subject is a element which is part of business letter.

hancock was president of congress when the declaration of independence was adopted and signed. he is primarily remembered by americans for his large, flamboyant signature on the declaration, so much so that "john hancock" became, in the united states, an informal synonym for signature.

explanation:

the sentence that avoid faulty coordination is:

culture, which is well represented in philadelphia, plays a major role including theatre, music, and the visual arts.  

faulty coordination occurs when the writer gives equal importance two different ideas (clauses) which in fact are not equivalent. in order to correct a misplaced clause or idea, the writer can place less important or emphatic ideas in a relative clause as in the previous sentence.