Question: some mice have a wheel in the middle. generally what is this wheel for
[{'answer': 'scrolling', 'provenance': [{'wikipedia_id': '1352971', 'title': 'Scroll wheel', 'start_paragraph_id': 3, 'start_character': 38, 'end_paragraph_id': 3, 'end_character': 47, 'bleu_score': 1.0, 'section': 'Section::::Functionality.\n'}]}, {'provenance': [{'wikipedia_id': '1352971', 'title': 'Scroll wheel', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 315, 'bleu_score': 0.860407220003034, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7970874920678787915}, 'section': 'Section::::Functionality.\n'}]}]