Question: where do the 6 carbon atoms in glucose come from
[{'answer': 'carbon dioxide', 'provenance': [{'wikipedia_id': '12950', 'title': 'Glucose', 'start_paragraph_id': 1, 'start_character': 240, 'end_paragraph_id': 1, 'end_character': 254, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]