Question: which part of potato plant is used as vegetable
[{'answer': 'stem', 'provenance': [{'wikipedia_id': '2254387', 'title': 'Edible plant stem', 'start_paragraph_id': 0, 'start_character': 13, 'end_paragraph_id': 0, 'end_character': 17, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '2254387', 'title': 'Edible plant stem', 'start_paragraph_id': 16, 'start_character': 19, 'end_paragraph_id': 16, 'end_character': 207, 'bleu_score': 0.882791692818587, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16882461171087909687}, 'section': 'Section::::Detailed description of edible plant stems.\n'}]}]