Question: when was the united nations formed and why
[{'answer': '24 October 1945', 'provenance': [{'wikipedia_id': '31769', 'title': 'United Nations', 'start_paragraph_id': 2, 'start_character': 303, 'end_paragraph_id': 2, 'end_character': 318, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'maintaining international peace and security', 'provenance': [{'wikipedia_id': '31769', 'title': 'United Nations', 'start_paragraph_id': 1, 'start_character': 73, 'end_paragraph_id': 1, 'end_character': 117, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'promoting human rights'}, {'answer': 'fostering social and economic development', 'provenance': [{'wikipedia_id': '31769', 'title': 'United Nations', 'start_paragraph_id': 23, 'start_character': 278, 'end_paragraph_id': 23, 'end_character': 313, 'bleu_score': 0.668740304976422, 'section': 'Section::::History.:Cold War era.\n'}]}, {'answer': 'protecting the environment'}, {'answer': 'providing humanitarian aid in cases of famine , natural disaster , and armed conflict'}, {'provenance': [{'wikipedia_id': '31769', 'title': 'United Nations', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 1031, 'bleu_score': 0.5161090515258481, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15881050123524675446}, 'section': 'Section::::Abstract.'}]}]