Question: where does the water come from in niagra falls
[{'answer': 'Niagara River', 'provenance': [{'wikipedia_id': '52028', 'title': 'Niagara Falls', 'start_paragraph_id': 2, 'start_character': 15, 'end_paragraph_id': 2, 'end_character': 28, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]