Question: who sings earth angel in back to the future
[{'answer': 'Harry Waters Jr.', 'provenance': [{'wikipedia_id': '762085', 'title': 'Earth Angel', 'start_paragraph_id': 17, 'start_character': 298, 'end_paragraph_id': 17, 'end_character': 314, 'bleu_score': 1.0, 'section': 'Section::::Cover versions and in popular culture.\n'}]}, {'provenance': [{'wikipedia_id': '762085', 'title': 'Earth Angel', 'start_paragraph_id': 17, 'start_character': 0, 'end_paragraph_id': 17, 'end_character': 585, 'bleu_score': 0.9802931511945101, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17132215024535399626}, 'section': 'Section::::Cover versions and in popular culture.\n'}]}]