Question: when is the heart developed in a fetus
[{'answer': 'by week 4 of development', 'provenance': [{'wikipedia_id': '39327375', 'title': 'Heart development', 'start_paragraph_id': 1, 'start_character': 440, 'end_paragraph_id': 1, 'end_character': 464, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '39327375', 'title': 'Heart development', 'start_paragraph_id': 1, 'start_character': 48, 'end_paragraph_id': 1, 'end_character': 464, 'bleu_score': 0.944041853942402, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5892613103708828137}, 'section': 'Section::::Abstract.'}]}]