Question: legal tender printed by the union during the civil war that was not backed by gold or silver
[{'answer': 'Greenbacks', 'provenance': [{'wikipedia_id': '12472957', 'title': 'Greenback (1860s money)', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 10, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '12472957', 'title': 'Greenback (1860s money)', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 338, 'bleu_score': 0.8495750370068681, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12158363550012502003}, 'section': 'Section::::Abstract.'}]}]