Question: what are the two main rivers in mesopotamia
[{'answer': 'the Tigris -- Euphrates river'}, {'provenance': [{'wikipedia_id': '20189', 'title': 'Mesopotamia', 'start_paragraph_id': 1, 'start_character': 46, 'end_paragraph_id': 1, 'end_character': 317, 'bleu_score': 0.720243969730959, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7189827097924381996}, 'section': 'Section::::Abstract.'}]}]