Question: where does the sound of lightning come from
[{'answer': 'expansion of air', 'provenance': [{'wikipedia_id': '94858', 'title': 'Thunder', 'start_paragraph_id': 1, 'start_character': 342, 'end_paragraph_id': 1, 'end_character': 358, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '94858', 'title': 'Thunder', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 455, 'bleu_score': 0.6455108708109271, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4807991521457937659}, 'section': 'Section::::Abstract.'}]}]