mariel was in a hurry she picked her books and started running she tripped why did mariel fall PLEASE

Because she was running and tripped.

If you are only allowed to use one use she tripped.

If the question is asking why did she trip it is because she was running.

Hope this helps. Comment if you still do not understand.

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.