Question: the tendency of urban areas to be warmer then the surrounding rural areas are caused by
[{'answer': 'human activities', 'provenance': [{'wikipedia_id': '32236', 'title': 'Urban heat island', 'start_paragraph_id': 1, 'start_character': 134, 'end_paragraph_id': 1, 'end_character': 150, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '32236', 'title': 'Urban heat island', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 696, 'bleu_score': 0.855535218651543, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14762946671044752221}, 'section': 'Section::::Abstract.'}]}]