Question: what type of gas is produced during fermentation
[{'answer': 'hydrogen gas ( H )', 'provenance': [{'wikipedia_id': '6073894', 'title': 'Fermentation', 'start_paragraph_id': 15, 'start_character': 251, 'end_paragraph_id': 15, 'end_character': 268, 'bleu_score': 1.0, 'section': 'Section::::Biochemical overview.\n'}]}, {'provenance': [{'wikipedia_id': '6073894', 'title': 'Fermentation', 'start_paragraph_id': 15, 'start_character': 0, 'end_paragraph_id': 15, 'end_character': 545, 'bleu_score': 0.9751504244977051, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17362924638538688538}, 'section': 'Section::::Biochemical overview.\n'}]}]