Question: where does mechanical digestion occur in the digestive system
[{'answer': 'the mouth', 'provenance': [{'wikipedia_id': '165423', 'title': 'Digestion', 'start_paragraph_id': 2, 'start_character': 43, 'end_paragraph_id': 2, 'end_character': 52, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'the stomach', 'provenance': [{'wikipedia_id': '165423', 'title': 'Digestion', 'start_paragraph_id': 2, 'start_character': 672, 'end_paragraph_id': 2, 'end_character': 683, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '165423', 'title': 'Digestion', 'start_paragraph_id': 2, 'start_character': 7, 'end_paragraph_id': 2, 'end_character': 1303, 'bleu_score': 0.933938120133709, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12974903385284761632}, 'section': 'Section::::Abstract.'}]}]