Question: studies have shown that the ice located in the south pole of mars is mostly
[{'answer': 'frozen carbon dioxide', 'provenance': [{'wikipedia_id': '28203358', 'title': 'Martian polar ice caps', 'start_paragraph_id': 13, 'start_character': 171, 'end_paragraph_id': 13, 'end_character': 192, 'bleu_score': 1.0, 'section': 'Section::::North polar cap.\n'}]}]