Question: which grain is said to be the staple food of more than one-third of the world's population
[{'answer': 'rice', 'provenance': [{'wikipedia_id': '47850038', 'title': 'Staple food', 'start_paragraph_id': 3, 'start_character': 112, 'end_paragraph_id': 3, 'end_character': 116, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '47850038', 'title': 'Staple food', 'start_paragraph_id': 7, 'start_character': 0, 'end_paragraph_id': 7, 'end_character': 275, 'bleu_score': 0.7684009668657921, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13376717140833284795}, 'section': 'Section::::Demographics.\n'}]}]