Question: what is the body natural version of morphine
[{'answer': 'Endorphins', 'provenance': [{'wikipedia_id': '60825', 'title': 'Endorphins', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 10, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '60825', 'title': 'Endorphins', 'start_paragraph_id': 1, 'start_character': 11, 'end_paragraph_id': 1, 'end_character': 953, 'bleu_score': 0.906891035349053, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9819486183980806031}, 'section': 'Section::::Abstract.'}]}]