Question: what the back part of the toilet called
[{'answer': 'cistern ( tank )', 'provenance': [{'wikipedia_id': '19167644', 'title': 'Toilet', 'start_paragraph_id': 12, 'start_character': 79, 'end_paragraph_id': 12, 'end_character': 98, 'bleu_score': 1.0, 'section': 'Section::::With water as an odor seal.:Flush toilet.\n'}]}, {'provenance': [{'wikipedia_id': '19167644', 'title': 'Toilet', 'start_paragraph_id': 12, 'start_character': 0, 'end_paragraph_id': 12, 'end_character': 401, 'bleu_score': 0.972407137066537, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12550722631222750103}, 'section': 'Section::::With water as an odor seal.:Flush toilet.\n'}]}]