Question: how old are the uwharrie mountains in north carolina
[{'answer': 'approximately 500 million years ago', 'provenance': [{'wikipedia_id': '1270453', 'title': 'Uwharrie Mountains', 'start_paragraph_id': 2, 'start_character': 189, 'end_paragraph_id': 2, 'end_character': 224, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1270453', 'title': 'Uwharrie Mountains', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 522, 'bleu_score': 0.9382880328341491, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4646021536343566733}, 'section': 'Section::::Abstract.'}]}]