Question: who was the greek physician who distinguished the veins from the arteries
[{'answer': 'Erasistratus', 'provenance': [{'wikipedia_id': '262935', 'title': 'Erasistratus', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 12, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '262935', 'title': 'Erasistratus', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 1002, 'bleu_score': 0.9664544610318541, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13313367197200645709}, 'section': 'Section::::Abstract.'}]}]