Question: which large vein carries blood from the head
[{'answer': 'superior vena cava', 'provenance': [{'wikipedia_id': '53227', 'title': 'Vein', 'start_paragraph_id': 14, 'start_character': 151, 'end_paragraph_id': 14, 'end_character': 169, 'bleu_score': 1.0, 'section': 'Section::::Structure.:Venous system.\n'}]}, {'provenance': [{'wikipedia_id': '53227', 'title': 'Vein', 'start_paragraph_id': 14, 'start_character': 0, 'end_paragraph_id': 14, 'end_character': 555, 'bleu_score': 0.980097014099621, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9698980946528357656}, 'section': 'Section::::Structure.:Venous system.\n'}]}]