Question: where did the heavier elements on earth come from
[{'answer': 'Supernova nucleosynthesis', 'provenance': [{'wikipedia_id': '48903', 'title': 'Nucleosynthesis', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 25, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]