What is the complete subject of the following sentence: billy buys buckets by the beach

Billy is the complete subject of this sentence because he is what the sentence is about.

Explanation:

Billy is the complete subject of this sentence because he is what the sentence is about.

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.