Question: when does the heart develop and begin pumping blood
[{'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.'}]}, {'answer': 'week 4 of development', 'provenance': [{'wikipedia_id': '39327375', 'title': 'Heart development', 'start_paragraph_id': 1, 'start_character': 443, 'end_paragraph_id': 1, 'end_character': 464, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'in the human , beats spontaneously by week 4 of development'}, {'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': 11276858871930703563}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '39327375', 'title': 'Heart development', 'start_paragraph_id': 9, 'start_character': 0, 'end_paragraph_id': 9, 'end_character': 1476, 'bleu_score': 0.9817126088325691, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11276858871930703563}, 'section': 'Section::::Early development.:Endocardial tubes.\n'}]}, {'provenance': [{'wikipedia_id': '5478198', 'title': 'Atrioventricular canal', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['The proper development of the atrioventricular canal into its prospective components (The heart septum and associated valves) to create a clear division between the four compartments of the heart and ensure proper blood movement through the heart, are essential for proper heart function. When this process does not happen correctly, a child will develop atrioventricular canal defect which occurs in 2 out of every 10,000 births. It also has a correlation with Down syndrome because 20% of children with Down syndrome suffer from atrioventricular canal disease as well. This is a very serious condition and surgery is necessary within the first six months of life for a child. Half of the children who are untreated with this condition die during their first year due to heart failure or pneumonia.', 'The proper development of the atrioventricular canal into its prospective components (The heart septum and associated valves) to create a clear division between the four compartments of the heart and ensure proper blood movement through the heart, are essential for proper heart function']}}]}, {'provenance': [{'wikipedia_id': '39327375', 'title': 'Heart development', 'section': 'Section::::Early development.:Endocardial tubes.\n', 'start_paragraph_id': 7, 'end_paragraph_id': 7, 'meta': {'evidence_span': ['endothelium, and myocardium. Mesothelial pericardium forms the outer lining of the heart. The inner lining of the heart, lymphatic and blood vessels, develop from endothelium. In the splanchnopleuric mesenchyme on either side of the neural plate, a horseshoe-shaped area develops as the cardiogenic region. This has formed from cardiac myoblasts and blood islands as forerunners of blood cells and vessels. By day 19, an endocardial tube begins to develop in each side of this region. These two tubes grow and by the third week have converged towards each other to merge, using programmed cell death to form a single tube, the tubular heart.', 'This has formed from cardiac myoblasts and blood islands as forerunners of blood cells and vessels. By day 19, an endocardial tube begins to develop in each side of this region. These two tubes grow and by the third week have converged towards each other to merge']}}]}, {'provenance': [{'wikipedia_id': '39327375', 'title': 'Heart development', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['Heart development (also known as cardiogenesis) refers to the prenatal development of the human heart. This begins with the formation of two endocardial tubes which merge to form the tubular heart, also called the "primitive heart tube", that loops and septates into the four chambers and paired arterial trunks that form the adult heart. The heart is the first functional organ in vertebrate embryos, and in the human, beats spontaneously by week 4 of development.', 'Heart development (also known as cardiogenesis) refers to the prenatal development of the human heart. This begins with the formation of two endocardial tubes which merge to form the tubular heart, also called the "primitive heart tube", that loops and septates into the four chambers and paired arterial trunks that form the adult heart.', 'The heart is the first functional organ in vertebrate embryos, and in the human, beats spontaneously by week 4 of development']}}]}]