Question: when did the first zoo in the world open
[{'answer': 'ca . 3500 BCE', 'provenance': [{'wikipedia_id': '9096372', 'title': 'Zoo', 'start_paragraph_id': 8, 'start_character': 233, 'end_paragraph_id': 8, 'end_character': 255, 'bleu_score': 1.0, 'section': 'Section::::History.:Royal menageries.\n'}]}, {'provenance': [{'wikipedia_id': '9096372', 'title': 'Zoo', 'start_paragraph_id': 8, 'start_character': 0, 'end_paragraph_id': 8, 'end_character': 1200, 'bleu_score': 0.950731426237958, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6859281117246364155}, 'section': 'Section::::History.:Royal menageries.\n'}]}]