Question: when did the first mammal appear on earth
[{'answer': 'late Carboniferous period', 'provenance': [{'wikipedia_id': '10727548', 'title': 'Evolution of mammals', 'start_paragraph_id': 1, 'start_character': 150, 'end_paragraph_id': 1, 'end_character': 175, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '10727548', 'title': 'Evolution of mammals', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 857, 'bleu_score': 0.747216591553944, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16658475459364556917}, 'section': 'Section::::Abstract.'}]}]