Question: where does the exchange of gasses occur in the lungs
[{'answer': 'the alveoli', 'provenance': [{'wikipedia_id': '379303', 'title': 'Gas exchange', 'start_paragraph_id': 2, 'start_character': 940, 'end_paragraph_id': 2, 'end_character': 951, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '379303', 'title': 'Gas exchange', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 1167, 'bleu_score': 0.970131808673194, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11801154746500664758}, 'section': 'Section::::Abstract.'}]}]