Question: which gases make up the largest percentage of earth's atmosphere
[{'answer': 'Nitrogen', 'provenance': [{'wikipedia_id': '202898', 'title': 'Atmosphere of Earth', 'start_paragraph_id': 2, 'start_character': 35, 'end_paragraph_id': 2, 'end_character': 43, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Oxygen', 'provenance': [{'wikipedia_id': '202898', 'title': 'Atmosphere of Earth', 'start_paragraph_id': 82, 'start_character': 343, 'end_paragraph_id': 82, 'end_character': 349, 'bleu_score': 1.0, 'section': "Section::::Evolution of Earth's atmosphere.:Second atmosphere.\n"}]}]