Question: where does mechanical digestion take place in the human 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.'}]}, {'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': 16394004141348215374}, 'section': 'Section::::Abstract.'}]}]