Question: who developed the world systems theory which explains how global stratification developed
[{'answer': 'Immanuel Wallerstein', 'provenance': [{'wikipedia_id': '1582335', 'title': 'World-systems theory', 'start_paragraph_id': 5, 'start_character': 0, 'end_paragraph_id': 5, 'end_character': 20, 'bleu_score': 1.0, 'section': 'Section::::Background.\n'}]}, {'provenance': [{'wikipedia_id': '1582335', 'title': 'World-systems theory', 'start_paragraph_id': 5, 'start_character': 0, 'end_paragraph_id': 5, 'end_character': 552, 'bleu_score': 0.8939523418860961, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11014528630401859092}, 'section': 'Section::::Background.\n'}]}]