Question: ball and socket joint is an example of
[{'answer': 'synovial joint', 'provenance': [{'wikipedia_id': '3596490', 'title': 'Ball-and-socket joint', 'start_paragraph_id': 1, 'start_character': 59, 'end_paragraph_id': 1, 'end_character': 73, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '3596490', 'title': 'Ball-and-socket joint', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 347, 'bleu_score': 0.9684940092844061, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3915832640969499341}, 'section': 'Section::::Abstract.'}]}]