Question: the chemical produced and secreted by the lining of the stomach is
[{'answer': 'Gastric acid', 'provenance': [{'wikipedia_id': '638449', 'title': 'Gastric acid', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 12, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '638449', 'title': 'Gastric acid', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 606, 'bleu_score': 0.60380701057912, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6700783194405680675}, 'section': 'Section::::Abstract.'}]}]