Question: the ____ limb of the loop of henle is impermeable to water
[{'answer': 'thin ascending', 'provenance': [{'wikipedia_id': '548777', 'title': 'Loop of Henle', 'start_paragraph_id': 6, 'start_character': 12, 'end_paragraph_id': 6, 'end_character': 26, 'bleu_score': 1.0, 'section': 'Section::::Structure.\n'}]}]