Question: what are saturn's rings mostly made of
[{'answer': 'water ice', 'provenance': [{'wikipedia_id': '977592', 'title': 'Rings of Saturn', 'start_paragraph_id': 1, 'start_character': 249, 'end_paragraph_id': 1, 'end_character': 258, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'rocky material', 'provenance': [{'wikipedia_id': '977592', 'title': 'Rings of Saturn', 'start_paragraph_id': 1, 'start_character': 286, 'end_paragraph_id': 1, 'end_character': 300, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '977592', 'title': 'Rings of Saturn', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 537, 'bleu_score': 0.706476753292478, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17914556066647422673}, 'section': 'Section::::Abstract.'}]}]