Question: universal joint is an example of which pair
[{'answer': 'lower pair', 'provenance': [{'wikipedia_id': '9536676', 'title': 'Kinematic pair', 'start_paragraph_id': 5, 'start_character': 108, 'end_paragraph_id': 5, 'end_character': 118, 'bleu_score': 1.0, 'section': 'Section::::Description.\n'}]}, {'provenance': [{'wikipedia_id': '9536676', 'title': 'Kinematic pair', 'start_paragraph_id': 7, 'start_character': 0, 'end_paragraph_id': 7, 'end_character': 299, 'bleu_score': 0.8973962687698531, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 18134173277638658645}, 'section': 'Section::::Lower pair.\n'}]}]