Question: to what group of organic compounds does hemoglobin belong
[{'answer': 'Heme or haem', 'provenance': [{'wikipedia_id': '97503', 'title': 'Heme', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 12, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '97503', 'title': 'Heme', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 604, 'bleu_score': 0.978375183951072, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3671600820205857069}, 'section': 'Section::::Abstract.'}]}]