Question: where are mast cells located in the body
[{'answer': 'blood', 'provenance': [{'wikipedia_id': '254062', 'title': 'Mast cell', 'start_paragraph_id': 1, 'start_character': 560, 'end_paragraph_id': 1, 'end_character': 565, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '254062', 'title': 'Mast cell', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 588, 'bleu_score': 0.793580953775029, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16038951663642493911}, 'section': 'Section::::Abstract.'}]}]