Question: what type of government system does the usa have
[{'answer': 'presidential system', 'provenance': [{'wikipedia_id': '206578', 'title': 'Presidential system', 'start_paragraph_id': 1, 'start_character': 2, 'end_paragraph_id': 1, 'end_character': 21, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '206578', 'title': 'Presidential system', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 264, 'bleu_score': 0.955027111100031, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6256187868213701870}, 'section': 'Section::::Abstract.'}]}]