Question: why coal came to be the dominant fuel source during the industrial revolution
[{'answer': 'to power steam engines', 'provenance': [{'wikipedia_id': '1454146', 'title': 'History of coal mining', 'start_paragraph_id': 1, 'start_character': 165, 'end_paragraph_id': 1, 'end_character': 187, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1454146', 'title': 'History of coal mining', 'start_paragraph_id': 15, 'start_character': 0, 'end_paragraph_id': 15, 'end_character': 751, 'bleu_score': 0.9831208473513011, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8353467928059358343}, 'section': 'Section::::Industrial Revolution.\n'}]}]