Question: what is the outermost layer of the atmosphere called
[{'answer': 'exosphere', 'provenance': [{'wikipedia_id': '202898', 'title': 'Atmosphere of Earth', 'start_paragraph_id': 10, 'start_character': 606, 'end_paragraph_id': 10, 'end_character': 615, 'bleu_score': 1.0, 'section': 'Section::::Stratification.\n'}]}, {'provenance': [{'wikipedia_id': '202898', 'title': 'Atmosphere of Earth', 'start_paragraph_id': 17, 'start_character': 0, 'end_paragraph_id': 17, 'end_character': 306, 'bleu_score': 0.9645876452711911, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10657916610096540054}, 'section': 'Section::::Stratification.:Exosphere.\n'}]}]